21748725 has 18 divisors (see below), whose sum is σ = 38954786. Its totient is φ = 11599200.

The previous prime is 21748717. The next prime is 21748747. The reversal of 21748725 is 52784712.

It can be written as a sum of positive squares in 3 ways, for example, as 4384836 + 17363889 = 2094^2 + 4167^2 .

It is not a de Polignac number, because 21748725 - 2³ = 21748717 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21748725.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 48106 + ... + 48555.

Almost surely, 2^21748725 is an apocalyptic number.

21748725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21748725 is a deficient number, since it is larger than the sum of its proper divisors (17206061).

21748725 is a wasteful number, since it uses less digits than its factorization.

21748725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96677 (or 96669 counting only the distinct ones).

The product of its digits is 31360, while the sum is 36.

The square root of 21748725 is about 4663.5528301929. The cubic root of 21748725 is about 279.1330540457.

The spelling of 21748725 in words is "twenty-one million, seven hundred forty-eight thousand, seven hundred twenty-five".