640036631 has 16 divisors (see below), whose sum is σ = 696292800. Its totient is φ = 588298464.

The previous prime is 640036601. The next prime is 640036637. The reversal of 640036631 is 136630046.

640036631 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 640036631 - 2²² = 635842327 is a prime.

It is a super-2 number, since 2×640036631² = 819293778043660322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 640036594 and 640036603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640036637) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 695990 + ... + 696908.

It is an arithmetic number, because the mean of its divisors is an integer number (43518300).

Almost surely, 2^640036631 is an apocalyptic number.

640036631 is a deficient number, since it is larger than the sum of its proper divisors (56256169).

640036631 is an equidigital number, since it uses as much as digits as its factorization.

640036631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1275 (or 1249 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 29.

The square root of 640036631 is about 25298.9452546939. The cubic root of 640036631 is about 861.7903171777.

Adding to 640036631 its reverse (136630046), we get a palindrome (776666677).

The spelling of 640036631 in words is "six hundred forty million, thirty-six thousand, six hundred thirty-one".