77640457 has 4 divisors (see below), whose sum is σ = 77714560. Its totient is φ = 77566356.

The previous prime is 77640443. The next prime is 77640509. The reversal of 77640457 is 75404677.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 75404677 = 2287 ⋅32971.

It is a cyclic number.

It is not a de Polignac number, because 77640457 - 2²³ = 69251849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77640427) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35457 + ... + 37582.

It is an arithmetic number, because the mean of its divisors is an integer number (19428640).

Almost surely, 2^77640457 is an apocalyptic number.

It is an amenable number.

77640457 is a deficient number, since it is larger than the sum of its proper divisors (74103).

77640457 is a wasteful number, since it uses less digits than its factorization.

77640457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74102.

The product of its (nonzero) digits is 164640, while the sum is 40.

The square root of 77640457 is about 8811.3822411697. The cubic root of 77640457 is about 426.6083592061.

The spelling of 77640457 in words is "seventy-seven million, six hundred forty thousand, four hundred fifty-seven".