21529825 has 12 divisors (see below), whose sum is σ = 26801980. Its totient is φ = 17156160.

The previous prime is 21529787. The next prime is 21529873. The reversal of 21529825 is 52892512.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 4875264 + 16654561 = 2208^2 + 4081^2 .

It is not a de Polignac number, because 21529825 - 2¹¹ = 21527777 is a prime.

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5371 + ... + 8479.

Almost surely, 2^21529825 is an apocalyptic number.

21529825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21529825 is a deficient number, since it is larger than the sum of its proper divisors (5272155).

21529825 is a wasteful number, since it uses less digits than its factorization.

21529825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3396 (or 3391 counting only the distinct ones).

The product of its digits is 14400, while the sum is 34.

The square root of 21529825 is about 4640.0242456263. The cubic root of 21529825 is about 278.1934069835.

The spelling of 21529825 in words is "twenty-one million, five hundred twenty-nine thousand, eight hundred twenty-five".