21992256 has 224 divisors, whose sum is σ = 76809600. Its totient is φ = 6082560.

The previous prime is 21992249. The next prime is 21992273. The reversal of 21992256 is 65229912.

It is a happy number.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21992256.

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 31 ways as a sum of consecutive naturals, for example, 247060 + ... + 247148.

It is an arithmetic number, because the mean of its divisors is an integer number (342900).

Almost surely, 2^21992256 is an apocalyptic number.

21992256 is a gapful number since it is divisible by the number (26) 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 21992256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38404800).

21992256 is an abundant number, since it is smaller than the sum of its proper divisors (54817344).

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

21992256 is a wasteful number, since it uses less digits than its factorization.

21992256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134 (or 118 counting only the distinct ones).

The product of its digits is 19440, while the sum is 36.

The square root of 21992256 is about 4689.5901739918. The cubic root of 21992256 is about 280.1710519457.

The spelling of 21992256 in words is "twenty-one million, nine hundred ninety-two thousand, two hundred fifty-six".