21159425 has 36 divisors (see below), whose sum is σ = 31890816. Its totient is φ = 13860000.

The previous prime is 21159389. The next prime is 21159427. The reversal of 21159425 is 52495112.

It is a de Polignac number, because none of the positive numbers 2^k-21159425 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21159427) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 27800 + ... + 28550.

It is an arithmetic number, because the mean of its divisors is an integer number (885856).

Almost surely, 2^21159425 is an apocalyptic number.

21159425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21159425 is a deficient number, since it is larger than the sum of its proper divisors (10731391).

21159425 is a wasteful number, since it uses less digits than its factorization.

21159425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 798 (or 786 counting only the distinct ones).

The product of its digits is 3600, while the sum is 29.

The square root of 21159425 is about 4599.9374995754. The cubic root of 21159425 is about 276.5888194067.

The spelling of 21159425 in words is "twenty-one million, one hundred fifty-nine thousand, four hundred twenty-five".