21917952 has 180 divisors, whose sum is σ = 75186496. Its totient is φ = 6220800.

The previous prime is 21917927. The next prime is 21917977. The reversal of 21917952 is 25971912.

It is an interprime number because it is at equal distance from previous prime (21917927) and next prime (21917977).

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

It is a nialpdrome in base 12.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 145077 + ... + 145227.

Almost surely, 2^21917952 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 21917952, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37593248).

21917952 is an abundant number, since it is smaller than the sum of its proper divisors (53268544).

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

21917952 is an equidigital number, since it uses as much as digits as its factorization.

21917952 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186 (or 163 counting only the distinct ones).

The product of its digits is 11340, while the sum is 36.

The square root of 21917952 is about 4681.6612436186. The cubic root of 21917952 is about 279.8551631878.

The spelling of 21917952 in words is "twenty-one million, nine hundred seventeen thousand, nine hundred fifty-two".