220643631 has 24 divisors (see below), whose sum is σ = 347373936. Its totient is φ = 134138880.

The previous prime is 220643627. The next prime is 220643651. The reversal of 220643631 is 136346022.

220643631 is a `hidden beast` number, since 2 + 20 + 6 + 4 + 3 + 631 = 666.

220643631 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 220643631 - 2² = 220643627 is a prime.

It is a super-2 number, since 2×220643631² = 97367223801728322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 220643595 and 220643604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (220643651) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1650 + ... + 21071.

It is an arithmetic number, because the mean of its divisors is an integer number (14473914).

Almost surely, 2^220643631 is an apocalyptic number.

220643631 is a deficient number, since it is larger than the sum of its proper divisors (126730305).

220643631 is a wasteful number, since it uses less digits than its factorization.

220643631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22823 (or 22820 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 27.

The square root of 220643631 is about 14854.0779249336. The cubic root of 220643631 is about 604.2692093715.

Adding to 220643631 its reverse (136346022), we get a palindrome (356989653).

The spelling of 220643631 in words is "two hundred twenty million, six hundred forty-three thousand, six hundred thirty-one".