21459725 has 24 divisors (see below), whose sum is σ = 30652800. Its totient is φ = 14598720.

The previous prime is 21459707. The next prime is 21459727. The reversal of 21459725 is 52795412.

It is not a de Polignac number, because 21459725 - 2¹⁶ = 21394189 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21459727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25664 + ... + 26486.

It is an arithmetic number, because the mean of its divisors is an integer number (1277200).

Almost surely, 2^21459725 is an apocalyptic number.

21459725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21459725 is a deficient number, since it is larger than the sum of its proper divisors (9193075).

21459725 is a wasteful number, since it uses less digits than its factorization.

21459725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 989 (or 984 counting only the distinct ones).

The product of its digits is 25200, while the sum is 35.

The square root of 21459725 is about 4632.4642470288. The cubic root of 21459725 is about 277.8911509064.

The spelling of 21459725 in words is "twenty-one million, four hundred fifty-nine thousand, seven hundred twenty-five".