12918822921 has 45 divisors (see below), whose sum is σ = 19680227589. Its totient is φ = 8445466944.

The previous prime is 12918822887. The next prime is 12918822953. The reversal of 12918822921 is 12922881921.

The square root of 12918822921 is 113661.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 3505942521 + 9412880400 = 59211^2 + 97020^2 .

It is not a de Polignac number, because 12918822921 - 2¹⁵ = 12918790153 is a prime.

It is not an unprimeable number, because it can be changed into a prime (12918822991) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 74675191 + ... + 74675363.

Almost surely, 2^12918822921 is an apocalyptic number.

12918822921 is the 113661-st square number.

12918822921 is the 56831-st centered octagonal number.

It is an amenable number.

12918822921 is a deficient number, since it is larger than the sum of its proper divisors (6761404668).

12918822921 is an frugal number, since it uses more digits than its factorization.

12918822921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 504 (or 249 counting only the distinct ones).

The product of its digits is 82944, while the sum is 45.

The spelling of 12918822921 in words is "twelve billion, nine hundred eighteen million, eight hundred twenty-two thousand, nine hundred twenty-one".