640711157 has 4 divisors (see below), whose sum is σ = 640795680. Its totient is φ = 640626636.

The previous prime is 640711133. The next prime is 640711189. The reversal of 640711157 is 751117046.

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.

It is a cyclic number.

It is not a de Polignac number, because 640711157 - 2⁸ = 640710901 is a prime.

It is a super-3 number, since 3×640711157³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640711457) 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, 29633 + ... + 46470.

It is an arithmetic number, because the mean of its divisors is an integer number (160198920).

Almost surely, 2^640711157 is an apocalyptic number.

It is an amenable number.

640711157 is a deficient number, since it is larger than the sum of its proper divisors (84523).

640711157 is an equidigital number, since it uses as much as digits as its factorization.

640711157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84522.

The product of its (nonzero) digits is 5880, while the sum is 32.

The square root of 640711157 is about 25312.2728533018. The cubic root of 640711157 is about 862.0929539637.

The spelling of 640711157 in words is "six hundred forty million, seven hundred eleven thousand, one hundred fifty-seven".