21535124 has 36 divisors (see below), whose sum is σ = 43143324. Its totient is φ = 9348096.

The previous prime is 21535123. The next prime is 21535169. The reversal of 21535124 is 42153512.

It can be written as a sum of positive squares in 6 ways, for example, as 1643524 + 19891600 = 1282^2 + 4460^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21535124.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21535121) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14312 + ... + 15744.

Almost surely, 2^21535124 is an apocalyptic number.

It is an amenable number.

21535124 is an abundant number, since it is smaller than the sum of its proper divisors (21608200).

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

21535124 is a wasteful number, since it uses less digits than its factorization.

21535124 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1484 (or 1465 counting only the distinct ones).

The product of its digits is 1200, while the sum is 23.

The square root of 21535124 is about 4640.5952204432. The cubic root of 21535124 is about 278.2162284407.

Adding to 21535124 its reverse (42153512), we get a palindrome (63688636).

The spelling of 21535124 in words is "twenty-one million, five hundred thirty-five thousand, one hundred twenty-four".