77491971 has 40 divisors (see below), whose sum is σ = 120930304. Its totient is φ = 49601160.

The previous prime is 77491963. The next prime is 77491979. The reversal of 77491971 is 17919477.

77491971 is a `hidden beast` number, since 77 + 491 + 97 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (77491963) and next prime (77491979).

It is not a de Polignac number, because 77491971 - 2³ = 77491963 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 (77491979) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 610110 + ... + 610236.

Almost surely, 2^77491971 is an apocalyptic number.

77491971 is a deficient number, since it is larger than the sum of its proper divisors (43438333).

77491971 is an frugal number, since it uses more digits than its factorization.

77491971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185 (or 161 counting only the distinct ones).

The product of its digits is 111132, while the sum is 45.

The square root of 77491971 is about 8802.9524024613. The cubic root of 77491971 is about 426.3362253362.

The spelling of 77491971 in words is "seventy-seven million, four hundred ninety-one thousand, nine hundred seventy-one".