79712928821 has 4 divisors (see below), whose sum is σ = 84401924652. Its totient is φ = 75023932992.

The previous prime is 79712928803. The next prime is 79712928853. The reversal of 79712928821 is 12882921797.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12882921797 = 16921 ⋅761357.

It can be written as a sum of positive squares in 2 ways, for example, as 46874415025 + 32838513796 = 216505^2 + 181214^2 .

It is a cyclic number.

It is not a de Polignac number, because 79712928821 - 2¹⁴ = 79712912437 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79712928121) 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, 2344497890 + ... + 2344497923.

It is an arithmetic number, because the mean of its divisors is an integer number (21100481163).

Almost surely, 2^79712928821 is an apocalyptic number.

It is an amenable number.

79712928821 is a deficient number, since it is larger than the sum of its proper divisors (4688995831).

79712928821 is a wasteful number, since it uses less digits than its factorization.

79712928821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4688995830.

The product of its digits is 2032128, while the sum is 56.

The spelling of 79712928821 in words is "seventy-nine billion, seven hundred twelve million, nine hundred twenty-eight thousand, eight hundred twenty-one".