12915451921 has 4 divisors (see below), whose sum is σ = 13215811312. Its totient is φ = 12615092532.

The previous prime is 12915451891. The next prime is 12915451931.

12915451921 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 12915451921 - 2²⁵ = 12881897489 is a prime.

It is a super-4 number, since 4×12915451921⁴ (a number of 42 digits) contains 4444 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12915451931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 150179631 + ... + 150179716.

It is an arithmetic number, because the mean of its divisors is an integer number (3303952828).

Almost surely, 2^12915451921 is an apocalyptic number.

It is an amenable number.

12915451921 is a deficient number, since it is larger than the sum of its proper divisors (300359391).

12915451921 is an equidigital number, since it uses as much as digits as its factorization.

12915451921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 300359390.

The product of its digits is 32400, while the sum is 40.

The spelling of 12915451921 in words is "twelve billion, nine hundred fifteen million, four hundred fifty-one thousand, nine hundred twenty-one".