20964564 has 72 divisors (see below), whose sum is σ = 56216160. Its totient is φ = 6576192.

The previous prime is 20964563. The next prime is 20964577. The reversal of 20964564 is 46546902.

20964564 is a `hidden beast` number, since 2 + 0 + 9 + 645 + 6 + 4 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20964563) 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, 44659 + ... + 45125.

It is an arithmetic number, because the mean of its divisors is an integer number (780780).

Almost surely, 2^20964564 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 20964564, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28108080).

20964564 is an abundant number, since it is smaller than the sum of its proper divisors (35251596).

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

20964564 is a wasteful number, since it uses less digits than its factorization.

20964564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 549 (or 544 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 20964564 is about 4578.7076779371. The cubic root of 20964564 is about 275.7371473534.

It can be divided in two parts, 20964 and 564, that added together give a triangular number (21528 = T₂₀₇).

The spelling of 20964564 in words is "twenty million, nine hundred sixty-four thousand, five hundred sixty-four".