643502631 has 8 divisors (see below), whose sum is σ = 881192944. Its totient is φ = 417407040.

The previous prime is 643502623. The next prime is 643502687. The reversal of 643502631 is 136205346.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 643502631 - 2³ = 643502623 is a prime.

It is a super-2 number, since 2×643502631² = 828191272207844322, 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 (643502731) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2898550 + ... + 2898771.

It is an arithmetic number, because the mean of its divisors is an integer number (110149118).

Almost surely, 2^643502631 is an apocalyptic number.

643502631 is a deficient number, since it is larger than the sum of its proper divisors (237690313).

643502631 is a wasteful number, since it uses less digits than its factorization.

643502631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5797361.

The product of its (nonzero) digits is 12960, while the sum is 30.

The square root of 643502631 is about 25367.3536459758. The cubic root of 643502631 is about 863.3431395589.

Adding to 643502631 its reverse (136205346), we get a palindrome (779707977).

The spelling of 643502631 in words is "six hundred forty-three million, five hundred two thousand, six hundred thirty-one".