21525524 has 12 divisors (see below), whose sum is σ = 38043348. Its totient is φ = 10656000.

The previous prime is 21525481. The next prime is 21525529. The reversal of 21525524 is 42552512.

It can be written as a sum of positive squares in 2 ways, for example, as 17073424 + 4452100 = 4132^2 + 2110^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21525493 and 21525502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21525529) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26237 + ... + 27044.

It is an arithmetic number, because the mean of its divisors is an integer number (3170279).

Almost surely, 2^21525524 is an apocalyptic number.

It is an amenable number.

21525524 is a deficient number, since it is larger than the sum of its proper divisors (16517824).

21525524 is a wasteful number, since it uses less digits than its factorization.

21525524 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53386 (or 53384 counting only the distinct ones).

The product of its digits is 4000, while the sum is 26.

The square root of 21525524 is about 4639.5607550715. The cubic root of 21525524 is about 278.1748809074.

The spelling of 21525524 in words is "twenty-one million, five hundred twenty-five thousand, five hundred twenty-four".