77975991 has 12 divisors (see below), whose sum is σ = 119257632. Its totient is φ = 48926016.

The previous prime is 77975969. The next prime is 77976001. The reversal of 77975991 is 19957977.

It is not a de Polignac number, because 77975991 - 2⁹ = 77975479 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77975921) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 254671 + ... + 254976.

It is an arithmetic number, because the mean of its divisors is an integer number (9938136).

Almost surely, 2^77975991 is an apocalyptic number.

77975991 is a deficient number, since it is larger than the sum of its proper divisors (41281641).

77975991 is a wasteful number, since it uses less digits than its factorization.

77975991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 509670 (or 509667 counting only the distinct ones).

The product of its digits is 1250235, while the sum is 54.

The square root of 77975991 is about 8830.4015197498. The cubic root of 77975991 is about 427.2220250974. Note that the first 3 decimals are identical.

The spelling of 77975991 in words is "seventy-seven million, nine hundred seventy-five thousand, nine hundred ninety-one".