21292656 has 120 divisors (see below), whose sum is σ = 69888384. Its totient is φ = 5523840.

The previous prime is 21292639. The next prime is 21292657. The reversal of 21292656 is 65629212.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21292657) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 25461 + ... + 26283.

Almost surely, 2^21292656 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 21292656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34944192).

21292656 is an abundant number, since it is smaller than the sum of its proper divisors (48595728).

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

21292656 is a wasteful number, since it uses less digits than its factorization.

21292656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 859 (or 846 counting only the distinct ones).

The product of its digits is 12960, while the sum is 33.

The square root of 21292656 is about 4614.3966019405. The cubic root of 21292656 is about 277.1681220356.

The spelling of 21292656 in words is "twenty-one million, two hundred ninety-two thousand, six hundred fifty-six".