21582372 has 48 divisors (see below), whose sum is σ = 60060672. Its totient is φ = 5897760.

The previous prime is 21582371. The next prime is 21582439. The reversal of 21582372 is 27328512.

It is a super-2 number, since 2×21582372² = 931597562292768, which contains 22 as substring.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21582371) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3654 + ... + 7517.

It is an arithmetic number, because the mean of its divisors is an integer number (1251264).

Almost surely, 2^21582372 is an apocalyptic number.

It is an amenable number.

21582372 is an abundant number, since it is smaller than the sum of its proper divisors (38478300).

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

21582372 is a wasteful number, since it uses less digits than its factorization.

21582372 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11208 (or 11206 counting only the distinct ones).

The product of its digits is 6720, while the sum is 30.

The square root of 21582372 is about 4645.6831575130. The cubic root of 21582372 is about 278.4195483532.

The spelling of 21582372 in words is "twenty-one million, five hundred eighty-two thousand, three hundred seventy-two".