79921076621 has 4 divisors (see below), whose sum is σ = 81275671200. Its totient is φ = 78566482044.

The previous prime is 79921076611. The next prime is 79921076629. The reversal of 79921076621 is 12667012997.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12667012997 = 613 ⋅20663969.

It is a cyclic number.

It is not a de Polignac number, because 79921076621 - 2¹⁴ = 79921060237 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 79921076621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79921076629) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 677297201 + ... + 677297318.

It is an arithmetic number, because the mean of its divisors is an integer number (20318917800).

Almost surely, 2^79921076621 is an apocalyptic number.

It is an amenable number.

79921076621 is a deficient number, since it is larger than the sum of its proper divisors (1354594579).

79921076621 is a wasteful number, since it uses less digits than its factorization.

79921076621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1354594578.

The product of its (nonzero) digits is 571536, while the sum is 50.

The spelling of 79921076621 in words is "seventy-nine billion, nine hundred twenty-one million, seventy-six thousand, six hundred twenty-one".