21511311324 has 24 divisors (see below), whose sum is σ = 51923855760. Its totient is φ = 6923180544.

The previous prime is 21511311319. The next prime is 21511311379. The reversal of 21511311324 is 42311311512.

It is a junction number, because it is equal to n+sod(n) for n = 21511311294 and 21511311303.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30906709 + ... + 30907404.

It is an arithmetic number, because the mean of its divisors is an integer number (2163493990).

Almost surely, 2^21511311324 is an apocalyptic number.

It is an amenable number.

21511311324 is an abundant number, since it is smaller than the sum of its proper divisors (30412544436).

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

21511311324 is a wasteful number, since it uses less digits than its factorization.

21511311324 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61814149 (or 61814147 counting only the distinct ones).

The product of its digits is 720, while the sum is 24.

Adding to 21511311324 its reverse (42311311512), we get a palindrome (63822622836).

The spelling of 21511311324 in words is "twenty-one billion, five hundred eleven million, three hundred eleven thousand, three hundred twenty-four".