79946511521 has 4 divisors (see below), whose sum is σ = 81301537200. Its totient is φ = 78591485844.

The previous prime is 79946511517. The next prime is 79946511539. The reversal of 79946511521 is 12511564997.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 79946511521 - 2² = 79946511517 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 79946511521.

It is not an unprimeable number, because it can be changed into a prime (79946571521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 677512751 + ... + 677512868.

It is an arithmetic number, because the mean of its divisors is an integer number (20325384300).

Almost surely, 2^79946511521 is an apocalyptic number.

It is an amenable number.

79946511521 is a deficient number, since it is larger than the sum of its proper divisors (1355025679).

79946511521 is a wasteful number, since it uses less digits than its factorization.

79946511521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1355025678.

The product of its digits is 680400, while the sum is 50.

The spelling of 79946511521 in words is "seventy-nine billion, nine hundred forty-six million, five hundred eleven thousand, five hundred twenty-one".