21456252 has 60 divisors (see below), whose sum is σ = 57324960. Its totient is φ = 6994944.

The previous prime is 21456251. The next prime is 21456257. The reversal of 21456252 is 25265412.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21456251) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 14524 + ... + 15932.

It is an arithmetic number, because the mean of its divisors is an integer number (955416).

Almost surely, 2^21456252 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 21456252, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28662480).

21456252 is an abundant number, since it is smaller than the sum of its proper divisors (35868708).

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

21456252 is a wasteful number, since it uses less digits than its factorization.

21456252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1472 (or 1461 counting only the distinct ones).

The product of its digits is 4800, while the sum is 27.

The square root of 21456252 is about 4632.0893773760. The cubic root of 21456252 is about 277.8761589772.

The spelling of 21456252 in words is "twenty-one million, four hundred fifty-six thousand, two hundred fifty-two".