77971691 has 24 divisors (see below), whose sum is σ = 96430320. Its totient is φ = 62741952.

The previous prime is 77971681. The next prime is 77971717. The reversal of 77971691 is 19617977.

It is not a de Polignac number, because 77971691 - 2²² = 73777387 is a prime.

It is not an unprimeable number, because it can be changed into a prime (77971631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 51836 + ... + 53318.

It is an arithmetic number, because the mean of its divisors is an integer number (4017930).

Almost surely, 2^77971691 is an apocalyptic number.

77971691 is a deficient number, since it is larger than the sum of its proper divisors (18458629).

77971691 is a wasteful number, since it uses less digits than its factorization.

77971691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1563 (or 1556 counting only the distinct ones).

The product of its digits is 166698, while the sum is 47.

The square root of 77971691 is about 8830.1580393558. The cubic root of 77971691 is about 427.2141718747.

The spelling of 77971691 in words is "seventy-seven million, nine hundred seventy-one thousand, six hundred ninety-one".