21513124 has 12 divisors (see below), whose sum is σ = 38358684. Its totient is φ = 10553504.

The previous prime is 21513113. The next prime is 21513127. The reversal of 21513124 is 42131512.

It can be written as a sum of positive squares in 2 ways, for example, as 12320100 + 9193024 = 3510^2 + 3032^2 .

It is not an unprimeable number, because it can be changed into a prime (21513127) 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, 50527 + ... + 50950.

It is an arithmetic number, because the mean of its divisors is an integer number (3196557).

Almost surely, 2^21513124 is an apocalyptic number.

It is an amenable number.

21513124 is a deficient number, since it is larger than the sum of its proper divisors (16845560).

21513124 is a wasteful number, since it uses less digits than its factorization.

21513124 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101534 (or 101532 counting only the distinct ones).

The product of its digits is 240, while the sum is 19.

The square root of 21513124 is about 4638.2242291636. The cubic root of 21513124 is about 278.1214554781.

Adding to 21513124 its reverse (42131512), we get a palindrome (63644636).

The spelling of 21513124 in words is "twenty-one million, five hundred thirteen thousand, one hundred twenty-four".