21525912 has 56 divisors (see below), whose sum is σ = 60530340. Its totient is φ = 7173360.

The previous prime is 21525901. The next prime is 21525937. The reversal of 21525912 is 21952512.

21525912 is a `hidden beast` number, since 21 + 52 + 591 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a zygodrome in base 3.

It is a congruent number.

It is an unprimeable number.

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 13 ways as a sum of consecutive naturals, for example, 3987 + ... + 7677.

Almost surely, 2^21525912 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 21525912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30265170).

21525912 is an abundant number, since it is smaller than the sum of its proper divisors (39004428).

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

21525912 is an equidigital number, since it uses as much as digits as its factorization.

21525912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3715 (or 3696 counting only the distinct ones).

The product of its digits is 1800, while the sum is 27.

The square root of 21525912 is about 4639.6025691863. The cubic root of 21525912 is about 278.1765522753.

The spelling of 21525912 in words is "twenty-one million, five hundred twenty-five thousand, nine hundred twelve".