640757873 has 8 divisors (see below), whose sum is σ = 732506880. Its totient is φ = 549061920.

The previous prime is 640757867. The next prime is 640757893. The reversal of 640757873 is 378757046.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 640757873 - 2⁴ = 640757857 is a prime.

It is a super-2 number, since 2×640757873² = 821141303622968258, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (640757893) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17333 + ... + 39773.

It is an arithmetic number, because the mean of its divisors is an integer number (91563360).

Almost surely, 2^640757873 is an apocalyptic number.

It is an amenable number.

640757873 is a deficient number, since it is larger than the sum of its proper divisors (91749007).

640757873 is a wasteful number, since it uses less digits than its factorization.

640757873 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26527.

The product of its (nonzero) digits is 987840, while the sum is 47.

The square root of 640757873 is about 25313.1956299476. The cubic root of 640757873 is about 862.1139059716.

The spelling of 640757873 in words is "six hundred forty million, seven hundred fifty-seven thousand, eight hundred seventy-three".