77698991 has 12 divisors (see below), whose sum is σ = 81755520. Its totient is φ = 73835520.

The previous prime is 77698987. The next prime is 77699009. The reversal of 77698991 is 19989677.

It is not a de Polignac number, because 77698991 - 2² = 77698987 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77698931) 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, 100655 + ... + 101423.

It is an arithmetic number, because the mean of its divisors is an integer number (6812960).

Almost surely, 2^77698991 is an apocalyptic number.

77698991 is a deficient number, since it is larger than the sum of its proper divisors (4056529).

77698991 is a wasteful number, since it uses less digits than its factorization.

77698991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1006 (or 983 counting only the distinct ones).

The product of its digits is 1714608, while the sum is 56.

The square root of 77698991 is about 8814.7031146829. The cubic root of 77698991 is about 426.7155405304.

The spelling of 77698991 in words is "seventy-seven million, six hundred ninety-eight thousand, nine hundred ninety-one".