21256992 has 120 divisors (see below), whose sum is σ = 64033200. Its totient is φ = 6915456.

The previous prime is 21256931. The next prime is 21256997. The reversal of 21256992 is 29965212.

It is a happy number.

21256992 is a `hidden beast` number, since 2 + 1 + 2 + 569 + 92 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (21256997) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 152859 + ... + 152997.

It is an arithmetic number, because the mean of its divisors is an integer number (533610).

Almost surely, 2^21256992 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 21256992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32016600).

21256992 is an abundant number, since it is smaller than the sum of its proper divisors (42776208).

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

21256992 is a wasteful number, since it uses less digits than its factorization.

21256992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220 (or 203 counting only the distinct ones).

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

The square root of 21256992 is about 4610.5305551531. The cubic root of 21256992 is about 277.0132885578.

The spelling of 21256992 in words is "twenty-one million, two hundred fifty-six thousand, nine hundred ninety-two".