12161556121 has 32 divisors (see below), whose sum is σ = 14637708288. Its totient is φ = 9958386240.

The previous prime is 12161556097. The next prime is 12161556151. The reversal of 12161556121 is 12165516121.

It is not a de Polignac number, because 12161556121 - 2⁵ = 12161556089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12161556151) 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, 1019236 + ... + 1031098.

It is an arithmetic number, because the mean of its divisors is an integer number (457428384).

Almost surely, 2^12161556121 is an apocalyptic number.

12161556121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12161556121 is a deficient number, since it is larger than the sum of its proper divisors (2476152167).

12161556121 is a wasteful number, since it uses less digits than its factorization.

12161556121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12061.

The product of its digits is 3600, while the sum is 31.

The spelling of 12161556121 in words is "twelve billion, one hundred sixty-one million, five hundred fifty-six thousand, one hundred twenty-one".