640652173 has 4 divisors (see below), whose sum is σ = 732173920. Its totient is φ = 549130428.

The previous prime is 640652147. The next prime is 640652209. The reversal of 640652173 is 371256046.

It is a happy number.

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 de Polignac number, because none of the positive numbers 2^k-640652173 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 (640655173) 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, 45760863 + ... + 45760876.

It is an arithmetic number, because the mean of its divisors is an integer number (183043480).

Almost surely, 2^640652173 is an apocalyptic number.

It is an amenable number.

640652173 is a deficient number, since it is larger than the sum of its proper divisors (91521747).

640652173 is an equidigital number, since it uses as much as digits as its factorization.

640652173 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91521746.

The product of its (nonzero) digits is 30240, while the sum is 34.

The square root of 640652173 is about 25311.1076999803. The cubic root of 640652173 is about 862.0664983340.

The spelling of 640652173 in words is "six hundred forty million, six hundred fifty-two thousand, one hundred seventy-three".