21582072 has 64 divisors (see below), whose sum is σ = 61437600. Its totient is φ = 7015680.

The previous prime is 21582049. The next prime is 21582097. The reversal of 21582072 is 27028512.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7638 + ... + 10074.

Almost surely, 2^21582072 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 21582072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30718800).

21582072 is an abundant number, since it is smaller than the sum of its proper divisors (39855528).

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

21582072 is a wasteful number, since it uses less digits than its factorization.

21582072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2493 (or 2483 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 21582072 is about 4645.6508693616. The cubic root of 21582072 is about 278.4182583150.

The spelling of 21582072 in words is "twenty-one million, five hundred eighty-two thousand, seventy-two".