21939925 has 12 divisors (see below), whose sum is σ = 31092256. Its totient is φ = 15044400.

The previous prime is 21939919. The next prime is 21939937. The reversal of 21939925 is 52993912.

It is not a de Polignac number, because 21939925 - 2¹³ = 21931733 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 11 ways as a sum of consecutive naturals, for example, 62511 + ... + 62860.

Almost surely, 2^21939925 is an apocalyptic number.

21939925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21939925 is a deficient number, since it is larger than the sum of its proper divisors (9152331).

21939925 is a wasteful number, since it uses less digits than its factorization.

21939925 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125388 (or 125383 counting only the distinct ones).

The product of its digits is 43740, while the sum is 40.

The square root of 21939925 is about 4684.0073654938. The cubic root of 21939925 is about 279.9486512981.

The spelling of 21939925 in words is "twenty-one million, nine hundred thirty-nine thousand, nine hundred twenty-five".