77921965 has 16 divisors (see below), whose sum is σ = 108008640. Its totient is φ = 53336320.

The previous prime is 77921951. The next prime is 77921981. The reversal of 77921965 is 56912977.

77921965 = 312² + 313² + ... + 641².

It is a happy number.

It is not a de Polignac number, because 77921965 - 2⁵ = 77921933 is a prime.

It is a super-2 number, since 2×77921965² = 12143665258922450, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40735 + ... + 42604.

It is an arithmetic number, because the mean of its divisors is an integer number (6750540).

Almost surely, 2^77921965 is an apocalyptic number.

It is an amenable number.

77921965 is a deficient number, since it is larger than the sum of its proper divisors (30086675).

77921965 is a wasteful number, since it uses less digits than its factorization.

77921965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83372.

The product of its digits is 238140, while the sum is 46.

The square root of 77921965 is about 8827.3418988957. The cubic root of 77921965 is about 427.1233347634.

The spelling of 77921965 in words is "seventy-seven million, nine hundred twenty-one thousand, nine hundred sixty-five".