21913992 has 96 divisors (see below), whose sum is σ = 63554400. Its totient is φ = 6801408.

The previous prime is 21913979. The next prime is 21914017. The reversal of 21913992 is 29931912.

It is a happy number.

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

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 113448 + ... + 113640.

It is an arithmetic number, because the mean of its divisors is an integer number (662025).

Almost surely, 2^21913992 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 21913992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31777200).

21913992 is an abundant number, since it is smaller than the sum of its proper divisors (41640408).

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

21913992 is a wasteful number, since it uses less digits than its factorization.

21913992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 307 (or 300 counting only the distinct ones).

The product of its digits is 8748, while the sum is 36.

The square root of 21913992 is about 4681.2382977157. The cubic root of 21913992 is about 279.8383080060.

The spelling of 21913992 in words is "twenty-one million, nine hundred thirteen thousand, nine hundred ninety-two".