12009748921 has 3 divisors (see below), whose sum is σ = 12009858511. Its totient is φ = 12009639332.

The previous prime is 12009748913. The next prime is 12009748943. The reversal of 12009748921 is 12984790021.

It is a happy number.

The square root of 12009748921 is 109589.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 237498921 + 11772250000 = 15411^2 + 108500^2 .

It is not a de Polignac number, because 12009748921 - 2³ = 12009748913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12009740921) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 54795 + ... + 164383.

Almost surely, 2^12009748921 is an apocalyptic number.

12009748921 is the 109589-th square number.

12009748921 is the 54795-th centered octagonal number.

It is an amenable number.

12009748921 is a deficient number, since it is larger than the sum of its proper divisors (109590).

12009748921 is an frugal number, since it uses more digits than its factorization.

12009748921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219178 (or 109589 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 43.

The spelling of 12009748921 in words is "twelve billion, nine million, seven hundred forty-eight thousand, nine hundred twenty-one".