79521021643 has 4 divisors (see below), whose sum is σ = 90881167600. Its totient is φ = 68160875688.

The previous prime is 79521021631. The next prime is 79521021653. The reversal of 79521021643 is 34612012597.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 79521021643 - 2²⁵ = 79487467211 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 79521021596 and 79521021605.

It is not an unprimeable number, because it can be changed into a prime (79521021653) 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, 5680072968 + ... + 5680072981.

It is an arithmetic number, because the mean of its divisors is an integer number (22720291900).

Almost surely, 2^79521021643 is an apocalyptic number.

79521021643 is a deficient number, since it is larger than the sum of its proper divisors (11360145957).

79521021643 is a wasteful number, since it uses less digits than its factorization.

79521021643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11360145956.

The product of its (nonzero) digits is 90720, while the sum is 40.

The spelling of 79521021643 in words is "seventy-nine billion, five hundred twenty-one million, twenty-one thousand, six hundred forty-three".