21229056 has 120 divisors (see below), whose sum is σ = 65111904. Its totient is φ = 6635520.

The previous prime is 21229051. The next prime is 21229063. The reversal of 21229056 is 65092212.

It is a super-2 number, since 2×21229056² = 901345637302272, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21229051) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 78201 + ... + 78471.

Almost surely, 2^21229056 is an apocalyptic number.

It is a pronic number, being equal to 4607×4608.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21229056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32555952).

21229056 is an abundant number, since it is smaller than the sum of its proper divisors (43882848).

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

21229056 is a wasteful number, since it uses less digits than its factorization.

21229056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 312 (or 293 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 21229056 is about 4607.4999728703. The cubic root of 21229056 is about 276.8918848058.

The spelling of 21229056 in words is "twenty-one million, two hundred twenty-nine thousand, fifty-six".