21153525 has 48 divisors (see below), whose sum is σ = 37926144. Its totient is φ = 10362880.

The previous prime is 21153497. The next prime is 21153533. The reversal of 21153525 is 52535112.

It is a happy number.

It is not a de Polignac number, because 21153525 - 2⁵ = 21153493 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21153495 and 21153504.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 59749 + ... + 60101.

It is an arithmetic number, because the mean of its divisors is an integer number (790128).

Almost surely, 2^21153525 is an apocalyptic number.

21153525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21153525 is a deficient number, since it is larger than the sum of its proper divisors (16772619).

21153525 is a wasteful number, since it uses less digits than its factorization.

21153525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 430 (or 425 counting only the distinct ones).

The product of its digits is 1500, while the sum is 24.

The square root of 21153525 is about 4599.2961418026. The cubic root of 21153525 is about 276.5631094180.

Adding to 21153525 its reverse (52535112), we get a palindrome (73688637).

The spelling of 21153525 in words is "twenty-one million, one hundred fifty-three thousand, five hundred twenty-five".