21311023122 has 48 divisors (see below), whose sum is σ = 46757032920. Its totient is φ = 7014180096.

The previous prime is 21311023109. The next prime is 21311023147. The reversal of 21311023122 is 22132011312.

It can be written as a sum of positive squares in 4 ways, for example, as 18122275161 + 3188747961 = 134619^2 + 56469^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21311023095 and 21311023104.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1203928 + ... + 1221500.

Almost surely, 2^21311023122 is an apocalyptic number.

21311023122 is an abundant number, since it is smaller than the sum of its proper divisors (25446009798).

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

21311023122 is a wasteful number, since it uses less digits than its factorization.

21311023122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18427 (or 18424 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 21311023122 its reverse (22132011312), we get a palindrome (43443034434).

The spelling of 21311023122 in words is "twenty-one billion, three hundred eleven million, twenty-three thousand, one hundred twenty-two".