21895920 has 200 divisors, whose sum is σ = 79221120. Its totient is φ = 5598720.

The previous prime is 21895883. The next prime is 21895921. The reversal of 21895920 is 2959812.

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 (21895921) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 200826 + ... + 200934.

Almost surely, 2^21895920 is an apocalyptic number.

21895920 is a gapful number since it is divisible by the number (20) 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 21895920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39610560).

21895920 is an abundant number, since it is smaller than the sum of its proper divisors (57325200).

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

21895920 is a wasteful number, since it uses less digits than its factorization.

21895920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165 (or 150 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 21895920 is about 4679.3076410939. The cubic root of 21895920 is about 279.7613612964.

The spelling of 21895920 in words is "twenty-one million, eight hundred ninety-five thousand, nine hundred twenty".