21531302124 has 48 divisors (see below), whose sum is σ = 50745397248. Its totient is φ = 7105105728.

The previous prime is 21531302119. The next prime is 21531302153. The reversal of 21531302124 is 42120313512.

It is a super-2 number, since 2×21531302124² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21531302094 and 21531302103.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 696582 + ... + 726834.

It is an arithmetic number, because the mean of its divisors is an integer number (1057195776).

Almost surely, 2^21531302124 is an apocalyptic number.

It is an amenable number.

21531302124 is an abundant number, since it is smaller than the sum of its proper divisors (29214095124).

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

21531302124 is a wasteful number, since it uses less digits than its factorization.

21531302124 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30854 (or 30852 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

Adding to 21531302124 its reverse (42120313512), we get a palindrome (63651615636).

The spelling of 21531302124 in words is "twenty-one billion, five hundred thirty-one million, three hundred two thousand, one hundred twenty-four".