21259056 has 160 divisors (see below), whose sum is σ = 70217728. Its totient is φ = 5391360.

The previous prime is 21259037. The next prime is 21259093. The reversal of 21259056 is 65095212.

It is a happy number.

It is a super-2 number, since 2×21259056² = 903894924022272, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 135330 + ... + 135486.

Almost surely, 2^21259056 is an apocalyptic number.

21259056 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 21259056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35108864).

21259056 is an abundant number, since it is smaller than the sum of its proper divisors (48958672).

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

21259056 is a wasteful number, since it uses less digits than its factorization.

21259056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 219 (or 213 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 30.

The square root of 21259056 is about 4610.7543851305. The cubic root of 21259056 is about 277.0222540302.

The spelling of 21259056 in words is "twenty-one million, two hundred fifty-nine thousand, fifty-six".