21576825 has 36 divisors (see below), whose sum is σ = 40927068. Its totient is φ = 10828800.

The previous prime is 21576817. The next prime is 21576827. The reversal of 21576825 is 52867512.

It is a happy number.

21576825 is a `hidden beast` number, since 2 + 1 + 576 + 82 + 5 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 2471184 + 19105641 = 1572^2 + 4371^2 .

It is not a de Polignac number, because 21576825 - 2³ = 21576817 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21576825.

It is not an unprimeable number, because it can be changed into a prime (21576827) by changing a digit.

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 35 ways as a sum of consecutive naturals, for example, 1005 + ... + 6645.

It is an arithmetic number, because the mean of its divisors is an integer number (1136863).

Almost surely, 2^21576825 is an apocalyptic number.

21576825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21576825 is a deficient number, since it is larger than the sum of its proper divisors (19350243).

21576825 is a wasteful number, since it uses less digits than its factorization.

21576825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5674 (or 5666 counting only the distinct ones).

The product of its digits is 33600, while the sum is 36.

The square root of 21576825 is about 4645.0861133030. The cubic root of 21576825 is about 278.3956936140.

The spelling of 21576825 in words is "twenty-one million, five hundred seventy-six thousand, eight hundred twenty-five".