21636525 has 24 divisors (see below), whose sum is σ = 36609760. Its totient is φ = 11269440.

The previous prime is 21636521. The next prime is 21636533. The reversal of 21636525 is 52563612.

It is not a de Polignac number, because 21636525 - 2² = 21636521 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a junction number, because it is equal to n+sod(n) for n = 21636492 and 21636501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21636521) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 130 + ... + 6579.

Almost surely, 2^21636525 is an apocalyptic number.

21636525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21636525 is a deficient number, since it is larger than the sum of its proper divisors (14973235).

21636525 is a wasteful number, since it uses less digits than its factorization.

21636525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6765 (or 6760 counting only the distinct ones).

The product of its digits is 10800, while the sum is 30.

The square root of 21636525 is about 4651.5078200515. The cubic root of 21636525 is about 278.6522175748.

The spelling of 21636525 in words is "twenty-one million, six hundred thirty-six thousand, five hundred twenty-five".