21472444 has 12 divisors (see below), whose sum is σ = 42944944. Its totient is φ = 9202464.

The previous prime is 21472433. The next prime is 21472453. The reversal of 21472444 is 44427412.

21472444 is an admirable number.

It is a super-2 number, since 2×21472444² = 922131702666272, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (28), and also a Moran number because the ratio is a prime number: 766873 = 21472444 / (2 + 1 + 4 + 7 + 2 + 4 + 4 + 4).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 383409 + ... + 383464.

Almost surely, 2^21472444 is an apocalyptic number.

It is an amenable number.

21472444 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21472444 is a wasteful number, since it uses less digits than its factorization.

21472444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 766884 (or 766882 counting only the distinct ones).

The product of its digits is 7168, while the sum is 28.

The square root of 21472444 is about 4633.8368551342. The cubic root of 21472444 is about 277.9460413192.

Adding to 21472444 its reverse (44427412), we get a palindrome (65899856).

The spelling of 21472444 in words is "twenty-one million, four hundred seventy-two thousand, four hundred forty-four".