21725748 has 72 divisors (see below), whose sum is σ = 60723936. Its totient is φ = 6494400.

The previous prime is 21725689. The next prime is 21725773. The reversal of 21725748 is 84752712.

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

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 32538 + ... + 33198.

It is an arithmetic number, because the mean of its divisors is an integer number (843388).

Almost surely, 2^21725748 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21725748, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30361968).

21725748 is an abundant number, since it is smaller than the sum of its proper divisors (38998188).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21725748 is a wasteful number, since it uses less digits than its factorization.

21725748 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 765 (or 760 counting only the distinct ones).

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

The square root of 21725748 is about 4661.0887140238. The cubic root of 21725748 is about 279.0347203100.

The spelling of 21725748 in words is "twenty-one million, seven hundred twenty-five thousand, seven hundred forty-eight".