21992320 has 64 divisors (see below), whose sum is σ = 60098400. Its totient is φ = 7538688.

The previous prime is 21992317. The next prime is 21992351. The reversal of 21992320 is 2329912.

It is a tau number, because it is divible by the number of its divisors (64).

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2026 + ... + 6934.

Almost surely, 2^21992320 is an apocalyptic number.

21992320 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 21992320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30049200).

21992320 is an abundant number, since it is smaller than the sum of its proper divisors (38106080).

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

21992320 is an equidigital number, since it uses as much as digits as its factorization.

21992320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4935 (or 4923 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 21992320 is about 4689.5969976108. The cubic root of 21992320 is about 280.1713237221.

The spelling of 21992320 in words is "twenty-one million, nine hundred ninety-two thousand, three hundred twenty".