20972864 has 56 divisors (see below), whose sum is σ = 46914816. Its totient is φ = 9225600.

The previous prime is 20972851. The next prime is 20972867. The reversal of 20972864 is 46827902.

It is a super-2 number, since 2×20972864² = 879722048724992, which contains 22 as substring.

It is a zygodrome in base 4.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20972867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 676529 + ... + 676559.

Almost surely, 2^20972864 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20972864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23457408).

20972864 is an abundant number, since it is smaller than the sum of its proper divisors (25941952).

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

20972864 is an frugal number, since it uses more digits than its factorization.

20972864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116 (or 44 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 38.

The square root of 20972864 is about 4579.6139575296. The cubic root of 20972864 is about 275.7735312306.

The spelling of 20972864 in words is "twenty million, nine hundred seventy-two thousand, eight hundred sixty-four".