21475925 has 6 divisors (see below), whose sum is σ = 26630178. Its totient is φ = 17180720.

The previous prime is 21475907. The next prime is 21475939. The reversal of 21475925 is 52957412.

It can be written as a sum of positive squares in 3 ways, for example, as 11236 + 21464689 = 106^2 + 4633^2 .

It is not a de Polignac number, because 21475925 - 2¹⁸ = 21213781 is a prime.

It is a super-2 number, since 2×21475925² = 922430709211250, which contains 22 as substring.

It is a Duffinian number.

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 5 ways as a sum of consecutive naturals, for example, 429494 + ... + 429543.

It is an arithmetic number, because the mean of its divisors is an integer number (4438363).

Almost surely, 2^21475925 is an apocalyptic number.

21475925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21475925 is a deficient number, since it is larger than the sum of its proper divisors (5154253).

21475925 is an equidigital number, since it uses as much as digits as its factorization.

21475925 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 859047 (or 859042 counting only the distinct ones).

The product of its digits is 25200, while the sum is 35.

The square root of 21475925 is about 4634.2124465760. The cubic root of 21475925 is about 277.9610602257.

The spelling of 21475925 in words is "twenty-one million, four hundred seventy-five thousand, nine hundred twenty-five".