21731124 has 24 divisors (see below), whose sum is σ = 52342528. Its totient is φ = 7009920.

The previous prime is 21731123. The next prime is 21731131. The reversal of 21731124 is 42113712.

It is a self number, because there is not a number n which added to its sum of digits gives 21731124.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21731123) 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, 28837 + ... + 29580.

Almost surely, 2^21731124 is an apocalyptic number.

It is an amenable number.

21731124 is an abundant number, since it is smaller than the sum of its proper divisors (30611404).

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

21731124 is a wasteful number, since it uses less digits than its factorization.

21731124 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58455 (or 58453 counting only the distinct ones).

The product of its digits is 336, while the sum is 21.

The square root of 21731124 is about 4661.6653676556. The cubic root of 21731124 is about 279.0577339701.

Adding to 21731124 its reverse (42113712), we get a palindrome (63844836).

The spelling of 21731124 in words is "twenty-one million, seven hundred thirty-one thousand, one hundred twenty-four".