21373224 has 16 divisors (see below), whose sum is σ = 53433120. Its totient is φ = 7124400.

The previous prime is 21373223. The next prime is 21373237. The reversal of 21373224 is 42237312.

It is a Harshad number since it is a multiple of its sum of digits (24), and also a Moran number because the ratio is a prime number: 890551 = 21373224 / (2 + 1 + 3 + 7 + 3 + 2 + 2 + 4).

It is a junction number, because it is equal to n+sod(n) for n = 21373194 and 21373203.

It is not an unprimeable number, because it can be changed into a prime (21373223) 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, 445252 + ... + 445299.

It is an arithmetic number, because the mean of its divisors is an integer number (3339570).

Almost surely, 2^21373224 is an apocalyptic number.

21373224 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21373224 is an abundant number, since it is smaller than the sum of its proper divisors (32059896).

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

21373224 is a wasteful number, since it uses less digits than its factorization.

21373224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 890560 (or 890556 counting only the distinct ones).

The product of its digits is 2016, while the sum is 24.

The square root of 21373224 is about 4623.1184280743. The cubic root of 21373224 is about 277.5172686275.

It can be divided in two parts, 213 and 73224, that added together give a palindrome (73437).

The spelling of 21373224 in words is "twenty-one million, three hundred seventy-three thousand, two hundred twenty-four".