79177961521 has 4 divisors (see below), whose sum is σ = 81732089344. Its totient is φ = 76623833700.

The previous prime is 79177961507. The next prime is 79177961531. The reversal of 79177961521 is 12516977197.

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: 12516977197 = 37 ⋅338296681.

It is a cyclic number.

It is not a de Polignac number, because 79177961521 - 2¹⁷ = 79177830449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (79177961531) 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, 1277063865 + ... + 1277063926.

It is an arithmetic number, because the mean of its divisors is an integer number (20433022336).

Almost surely, 2^79177961521 is an apocalyptic number.

It is an amenable number.

79177961521 is a deficient number, since it is larger than the sum of its proper divisors (2554127823).

79177961521 is a wasteful number, since it uses less digits than its factorization.

79177961521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2554127822.

The product of its digits is 1666980, while the sum is 55.

The spelling of 79177961521 in words is "seventy-nine billion, one hundred seventy-seven million, nine hundred sixty-one thousand, five hundred twenty-one".