640237631 has 8 divisors (see below), whose sum is σ = 700002000. Its totient is φ = 580733440.

The previous prime is 640237573. The next prime is 640237651. The reversal of 640237631 is 136732046.

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 640237631 - 2²² = 636043327 is a prime.

It is a super-2 number, since 2×640237631² = 819808448296984322, which contains 22 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 (640237651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 59876 + ... + 69753.

It is an arithmetic number, because the mean of its divisors is an integer number (87500250).

Almost surely, 2^640237631 is an apocalyptic number.

640237631 is a deficient number, since it is larger than the sum of its proper divisors (59764369).

640237631 is a wasteful number, since it uses less digits than its factorization.

640237631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130089.

The product of its (nonzero) digits is 18144, while the sum is 32.

The square root of 640237631 is about 25302.9174404850. The cubic root of 640237631 is about 861.8805212460.

Adding to 640237631 its reverse (136732046), we get a palindrome (776969677).

The spelling of 640237631 in words is "six hundred forty million, two hundred thirty-seven thousand, six hundred thirty-one".