12165123921 has 32 divisors (see below), whose sum is σ = 16997126400. Its totient is φ = 7731521280.

The previous prime is 12165123907. The next prime is 12165123931. The reversal of 12165123921 is 12932156121.

It is a happy number.

It is not a de Polignac number, because 12165123921 - 2⁷ = 12165123793 is a prime.

It is a super-4 number, since 4×12165123921⁴ (a number of 41 digits) contains 4444 as substring.

It is not an unprimeable number, because it can be changed into a prime (12165123931) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1818060 + ... + 1824738.

It is an arithmetic number, because the mean of its divisors is an integer number (531160200).

Almost surely, 2^12165123921 is an apocalyptic number.

It is an amenable number.

12165123921 is a deficient number, since it is larger than the sum of its proper divisors (4832002479).

12165123921 is a wasteful number, since it uses less digits than its factorization.

12165123921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7049.

The product of its digits is 6480, while the sum is 33.

The spelling of 12165123921 in words is "twelve billion, one hundred sixty-five million, one hundred twenty-three thousand, nine hundred twenty-one".