21489725 has 12 divisors (see below), whose sum is σ = 27567060. Its totient is φ = 16598400.

The previous prime is 21489719. The next prime is 21489731. The reversal of 21489725 is 52798412.

It is an interprime number because it is at equal distance from previous prime (21489719) and next prime (21489731).

It can be written as a sum of positive squares in 6 ways, for example, as 458329 + 21031396 = 677^2 + 4586^2 .

It is not a de Polignac number, because 21489725 - 2⁶ = 21489661 is a prime.

It is a hoax number, since the sum of its digits (38) coincides with the sum of the digits of its distinct prime factors.

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, 14096 + ... + 15545.

It is an arithmetic number, because the mean of its divisors is an integer number (2297255).

Almost surely, 2^21489725 is an apocalyptic number.

21489725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21489725 is a deficient number, since it is larger than the sum of its proper divisors (6077335).

21489725 is a wasteful number, since it uses less digits than its factorization.

21489725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29680 (or 29675 counting only the distinct ones).

The product of its digits is 40320, while the sum is 38.

The square root of 21489725 is about 4635.7011335935. The cubic root of 21489725 is about 278.0205848843.

The spelling of 21489725 in words is "twenty-one million, four hundred eighty-nine thousand, seven hundred twenty-five".