79660391021 has 24 divisors (see below), whose sum is σ = 85476907200. Its totient is φ = 74033464320.

The previous prime is 79660391011. The next prime is 79660391051. The reversal of 79660391021 is 12019306697.

It is not a de Polignac number, because 79660391021 - 2¹⁰ = 79660389997 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79660391011) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 42394160 + ... + 42396038.

It is an arithmetic number, because the mean of its divisors is an integer number (3561537800).

Almost surely, 2^79660391021 is an apocalyptic number.

It is an amenable number.

79660391021 is a deficient number, since it is larger than the sum of its proper divisors (5816516179).

79660391021 is a wasteful number, since it uses less digits than its factorization.

79660391021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2657 (or 2598 counting only the distinct ones).

The product of its (nonzero) digits is 122472, while the sum is 44.

The spelling of 79660391021 in words is "seventy-nine billion, six hundred sixty million, three hundred ninety-one thousand, twenty-one".