21440472 has 32 divisors (see below), whose sum is σ = 53995200. Its totient is φ = 7094304.

The previous prime is 21440453. The next prime is 21440473. The reversal of 21440472 is 27404412.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21440473) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 123 + ... + 6549.

It is an arithmetic number, because the mean of its divisors is an integer number (1687350).

Almost surely, 2^21440472 is an apocalyptic number.

It is an amenable number.

21440472 is an abundant number, since it is smaller than the sum of its proper divisors (32554728).

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

21440472 is a wasteful number, since it uses less digits than its factorization.

21440472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6575 (or 6571 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 24.

The square root of 21440472 is about 4630.3857290727. The cubic root of 21440472 is about 277.8080209323.

Adding to 21440472 its reverse (27404412), we get a palindrome (48844884).

It can be divided in two parts, 21440 and 472, that added together give a palindrome (21912).

The spelling of 21440472 in words is "twenty-one million, four hundred forty thousand, four hundred seventy-two".