20975904 has 72 divisors (see below), whose sum is σ = 60137532. Its totient is φ = 6935040.

The previous prime is 20975881. The next prime is 20975923. The reversal of 20975904 is 40957902.

It can be written as a sum of positive squares in 2 ways, for example, as 20684304 + 291600 = 4548^2 + 540^2 .

It is a tau number, because it is divible by the number of its divisors (72).

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

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 49614 + ... + 50034.

Almost surely, 2^20975904 is an apocalyptic number.

20975904 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20975904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30068766).

20975904 is an abundant number, since it is smaller than the sum of its proper divisors (39161628).

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

20975904 is a wasteful number, since it uses less digits than its factorization.

20975904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 610 (or 599 counting only the distinct ones).

The product of its (nonzero) digits is 22680, while the sum is 36.

The square root of 20975904 is about 4579.9458512083. The cubic root of 20975904 is about 275.7868549717.

It can be divided in two parts, 2097 and 5904, that added together give a triangular number (8001 = T₁₂₆).

The spelling of 20975904 in words is "twenty million, nine hundred seventy-five thousand, nine hundred four".