640724017 has 4 divisors (see below), whose sum is σ = 645769216. Its totient is φ = 635678820.

The previous prime is 640723997. The next prime is 640724111. The reversal of 640724017 is 710427046.

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 640724017 - 2²⁷ = 506506289 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 640724017.

It is not an unprimeable number, because it can be changed into a prime (640794017) 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, 2522409 + ... + 2522662.

It is an arithmetic number, because the mean of its divisors is an integer number (161442304).

Almost surely, 2^640724017 is an apocalyptic number.

It is an amenable number.

640724017 is a deficient number, since it is larger than the sum of its proper divisors (5045199).

640724017 is a wasteful number, since it uses less digits than its factorization.

640724017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5045198.

The product of its (nonzero) digits is 9408, while the sum is 31.

The square root of 640724017 is about 25312.5268789981. The cubic root of 640724017 is about 862.0987217428.

The spelling of 640724017 in words is "six hundred forty million, seven hundred twenty-four thousand, seventeen".