21572384 has 24 divisors (see below), whose sum is σ = 42604380. Its totient is φ = 10752256.

The previous prime is 21572363. The next prime is 21572387. The reversal of 21572384 is 48327512.

It can be written as a sum of positive squares in 2 ways, for example, as 20976400 + 595984 = 4580^2 + 772^2 .

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a self number, because there is not a number n which added to its sum of digits gives 21572384.

It is not an unprimeable number, because it can be changed into a prime (21572387) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11582 + ... + 13314.

Almost surely, 2^21572384 is an apocalyptic number.

It is an amenable number.

21572384 is a deficient number, since it is larger than the sum of its proper divisors (21031996).

21572384 is a wasteful number, since it uses less digits than its factorization.

21572384 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2132 (or 2124 counting only the distinct ones).

The product of its digits is 13440, while the sum is 32.

The square root of 21572384 is about 4644.6080566610. The cubic root of 21572384 is about 278.3765922540.

Adding to 21572384 its reverse (48327512), we get a palindrome (69899896).

The spelling of 21572384 in words is "twenty-one million, five hundred seventy-two thousand, three hundred eighty-four".