21739425 has 12 divisors (see below), whose sum is σ = 35942640. Its totient is φ = 11594320.

The previous prime is 21739411. The next prime is 21739433. The reversal of 21739425 is 52493712.

It is not a de Polignac number, because 21739425 - 2⁴ = 21739409 is a prime.

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, 144855 + ... + 145004.

It is an arithmetic number, because the mean of its divisors is an integer number (2995220).

Almost surely, 2^21739425 is an apocalyptic number.

21739425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21739425 is a deficient number, since it is larger than the sum of its proper divisors (14203215).

21739425 is a wasteful number, since it uses less digits than its factorization.

21739425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 289872 (or 289867 counting only the distinct ones).

The product of its digits is 15120, while the sum is 33.

The square root of 21739425 is about 4662.5556296949. Note that the first 3 decimals coincide. The cubic root of 21739425 is about 279.0932615597.

The spelling of 21739425 in words is "twenty-one million, seven hundred thirty-nine thousand, four hundred twenty-five".