21512343122 has 4 divisors (see below), whose sum is σ = 32268514686. Its totient is φ = 10756171560.

The previous prime is 21512343059. The next prime is 21512343137. The reversal of 21512343122 is 22134321512.

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., 19363000801 + 2149342321 = 139151^2 + 46361^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21512343091 and 21512343100.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5378085779 + ... + 5378085782.

Almost surely, 2^21512343122 is an apocalyptic number.

21512343122 is a deficient number, since it is larger than the sum of its proper divisors (10756171564).

21512343122 is a wasteful number, since it uses less digits than its factorization.

21512343122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10756171563.

The product of its digits is 2880, while the sum is 26.

Adding to 21512343122 its reverse (22134321512), we get a palindrome (43646664634).

The spelling of 21512343122 in words is "twenty-one billion, five hundred twelve million, three hundred forty-three thousand, one hundred twenty-two".