21311123122 has 4 divisors (see below), whose sum is σ = 31966684686. Its totient is φ = 10655561560.

The previous prime is 21311123051. The next prime is 21311123147. The reversal of 21311123122 is 22132111312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 21310452361 + 670761 = 145981^2 + 819^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21311123122.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5327780779 + ... + 5327780782.

Almost surely, 2^21311123122 is an apocalyptic number.

21311123122 is a deficient number, since it is larger than the sum of its proper divisors (10655561564).

21311123122 is a wasteful number, since it uses less digits than its factorization.

21311123122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10655561563.

The product of its digits is 144, while the sum is 19.

Adding to 21311123122 its reverse (22132111312), we get a palindrome (43443234434).

The spelling of 21311123122 in words is "twenty-one billion, three hundred eleven million, one hundred twenty-three thousand, one hundred twenty-two".