20990772 has 48 divisors (see below), whose sum is σ = 59371200. Its totient is φ = 6360480.

The previous prime is 20990759. The next prime is 20990773. The reversal of 20990772 is 27709902.

It is a super-2 number, since 2×20990772² = 881225018311968, which contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

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 (20990773) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7647 + ... + 10022.

It is an arithmetic number, because the mean of its divisors is an integer number (1236900).

Almost surely, 2^20990772 is an apocalyptic number.

20990772 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

20990772 is an abundant number, since it is smaller than the sum of its proper divisors (38380428).

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

20990772 is a wasteful number, since it uses less digits than its factorization.

20990772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17693 (or 17685 counting only the distinct ones).

The product of its (nonzero) digits is 15876, while the sum is 36.

The square root of 20990772 is about 4581.5687269755. The cubic root of 20990772 is about 275.8520000470.

The spelling of 20990772 in words is "twenty million, nine hundred ninety thousand, seven hundred seventy-two".