12158105921 has 4 divisors (see below), whose sum is σ = 13093344852. Its totient is φ = 11222866992.

The previous prime is 12158105891. The next prime is 12158105933. The reversal of 12158105921 is 12950185121.

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

It can be written as a sum of positive squares in 2 ways, for example, as 3102490000 + 9055615921 = 55700^2 + 95161^2 .

It is a cyclic number.

It is not a de Polignac number, because 12158105921 - 2⁶ = 12158105857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12158105321) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 467619446 + ... + 467619471.

It is an arithmetic number, because the mean of its divisors is an integer number (3273336213).

Almost surely, 2^12158105921 is an apocalyptic number.

It is an amenable number.

12158105921 is a deficient number, since it is larger than the sum of its proper divisors (935238931).

12158105921 is an equidigital number, since it uses as much as digits as its factorization.

12158105921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 935238930.

The product of its (nonzero) digits is 7200, while the sum is 35.

The spelling of 12158105921 in words is "twelve billion, one hundred fifty-eight million, one hundred five thousand, nine hundred twenty-one".