21930925 has 6 divisors (see below), whose sum is σ = 27194378. Its totient is φ = 17544720.

The previous prime is 21930917. The next prime is 21930991. The reversal of 21930925 is 52903912.

It can be written as a sum of positive squares in 3 ways, for example, as 9801 + 21921124 = 99^2 + 4682^2 .

It is not a de Polignac number, because 21930925 - 2³ = 21930917 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 438594 + ... + 438643.

Almost surely, 2^21930925 is an apocalyptic number.

21930925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21930925 is a deficient number, since it is larger than the sum of its proper divisors (5263453).

21930925 is an equidigital number, since it uses as much as digits as its factorization.

21930925 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 877247 (or 877242 counting only the distinct ones).

The product of its (nonzero) digits is 4860, while the sum is 31.

The square root of 21930925 is about 4683.0465511246. The cubic root of 21930925 is about 279.9103667179.

The spelling of 21930925 in words is "twenty-one million, nine hundred thirty thousand, nine hundred twenty-five".