21682825 has 18 divisors (see below), whose sum is σ = 27507354. Its totient is φ = 16951680.

The previous prime is 21682823. The next prime is 21682847. The reversal of 21682825 is 52828612.

It can be written as a sum of positive squares in 9 ways, for example, as 1871424 + 19811401 = 1368^2 + 4451^2 .

It is not a de Polignac number, because 21682825 - 2¹ = 21682823 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21682823) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 198871 + ... + 198979.

Almost surely, 2^21682825 is an apocalyptic number.

21682825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21682825 is a deficient number, since it is larger than the sum of its proper divisors (5824529).

21682825 is an equidigital number, since it uses as much as digits as its factorization.

21682825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 301 (or 187 counting only the distinct ones).

The product of its digits is 15360, while the sum is 34.

The square root of 21682825 is about 4656.4820411981. The cubic root of 21682825 is about 278.8508385932.

The spelling of 21682825 in words is "twenty-one million, six hundred eighty-two thousand, eight hundred twenty-five".