21065472 has 108 divisors (see below), whose sum is σ = 62497344. Its totient is φ = 6819840.

The previous prime is 21065459. The next prime is 21065477. The reversal of 21065472 is 27456012.

21065472 is a `hidden beast` number, since 2 + 1 + 0 + 654 + 7 + 2 = 666.

It is a super-2 number, since 2×21065472² = 887508221165568, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21065477) 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, 94353 + ... + 94575.

Almost surely, 2^21065472 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 21065472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31248672).

21065472 is an abundant number, since it is smaller than the sum of its proper divisors (41431872).

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

21065472 is a wasteful number, since it uses less digits than its factorization.

21065472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 286 (or 269 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 21065472 is about 4589.7137165623. The cubic root of 21065472 is about 276.1788380956.

The spelling of 21065472 in words is "twenty-one million, sixty-five thousand, four hundred seventy-two".