21373124 has 12 divisors (see below), whose sum is σ = 38414124. Its totient is φ = 10397664.

The previous prime is 21373123. The next prime is 21373129. The reversal of 21373124 is 42137312.

It can be written as a sum of positive squares in 2 ways, for example, as 9193024 + 12180100 = 3032^2 + 3490^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21373124.

It is not an unprimeable number, because it can be changed into a prime (21373123) 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, 72059 + ... + 72354.

It is an arithmetic number, because the mean of its divisors is an integer number (3201177).

Almost surely, 2^21373124 is an apocalyptic number.

It is an amenable number.

21373124 is a deficient number, since it is larger than the sum of its proper divisors (17041000).

21373124 is a wasteful number, since it uses less digits than its factorization.

21373124 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144454 (or 144452 counting only the distinct ones).

The product of its digits is 1008, while the sum is 23.

The square root of 21373124 is about 4623.1076128509. The cubic root of 21373124 is about 277.5168358154.

It can be divided in two parts, 213 and 73124, that added together give a palindrome (73337).

The spelling of 21373124 in words is "twenty-one million, three hundred seventy-three thousand, one hundred twenty-four".