20639268 has 36 divisors (see below), whose sum is σ = 56185948. Its totient is φ = 6350400.

The previous prime is 20639261. The next prime is 20639279. The reversal of 20639268 is 86293602.

20639268 is a `hidden beast` number, since 206 + 392 + 68 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 14197824 + 6441444 = 3768^2 + 2538^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (20639261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21583 + ... + 22518.

Almost surely, 2^20639268 is an apocalyptic number.

It is an amenable number.

20639268 is an abundant number, since it is smaller than the sum of its proper divisors (35546680).

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

20639268 is a wasteful number, since it uses less digits than its factorization.

20639268 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44124 (or 44119 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 20639268 is about 4543.0461146680. The cubic root of 20639268 is about 274.3035512024.

The spelling of 20639268 in words is "twenty million, six hundred thirty-nine thousand, two hundred sixty-eight".