643612631 has 16 divisors (see below), whose sum is σ = 707119200. Its totient is φ = 583446528.

The previous prime is 643612621. The next prime is 643612643. The reversal of 643612631 is 136216346.

It is a de Polignac number, because none of the positive numbers 2^k-643612631 is a prime.

It is a super-2 number, since 2×643612631² = 828474437565484322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643612621) 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, 57095 + ... + 67431.

It is an arithmetic number, because the mean of its divisors is an integer number (44194950).

Almost surely, 2^643612631 is an apocalyptic number.

643612631 is a deficient number, since it is larger than the sum of its proper divisors (63506569).

643612631 is a wasteful number, since it uses less digits than its factorization.

643612631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10498.

The product of its digits is 15552, while the sum is 32.

The square root of 643612631 is about 25369.5216943481. The cubic root of 643612631 is about 863.3923298963.

Adding to 643612631 its reverse (136216346), we get a palindrome (779828977).

The spelling of 643612631 in words is "six hundred forty-three million, six hundred twelve thousand, six hundred thirty-one".