20631564 has 24 divisors (see below), whose sum is σ = 53489520. Its totient is φ = 6877152.

The previous prime is 20631563. The next prime is 20631571. The reversal of 20631564 is 46513602.

20631564 is a `hidden beast` number, since 20 + 631 + 5 + 6 + 4 = 666.

It is a super-2 number, since 2×20631564² = 851322866172192, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (20631563) 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, 95409 + ... + 95624.

It is an arithmetic number, because the mean of its divisors is an integer number (2228730).

Almost surely, 2^20631564 is an apocalyptic number.

It is an amenable number.

20631564 is an abundant number, since it is smaller than the sum of its proper divisors (32857956).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20631564 is a wasteful number, since it uses less digits than its factorization.

20631564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191046 (or 191038 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 20631564 is about 4542.1981462724. The cubic root of 20631564 is about 274.2694172795.

The spelling of 20631564 in words is "twenty million, six hundred thirty-one thousand, five hundred sixty-four".