Exhibit 32.1

CERTIFICATION OF PRINCIPAL EXECUTIVE OFFICER AND PRINCIPAL FINANCIAL OFFICER

PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of Actinium Pharmaceuticals, Inc. (the “Company”) on Form 10-Q for the period ended June 30, 2026 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Sandesh Seth, Chairman & CEO of the Company, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that:

| 1. | The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and

| 2. | The information contained in the Quarterly Report fairly presents, in all material respects, the financial condition and result of operations of the Company.

Date: August 7, 2026 | By: | /s/ Sandesh Seth
|  | Sandesh Seth
|  | Chairman and Chief Executive Officer
|  | (Duly Authorized Officer, Principal
|  | Executive Officer, Principal Financial
|  | Officer)