12165561243 has 72 divisors (see below), whose sum is σ = 20483087040. Its totient is φ = 6881263200.

The previous prime is 12165561217. The next prime is 12165561251. The reversal of 12165561243 is 34216556121.

12165561243 is a `hidden beast` number, since 12 + 1 + 65 + 561 + 24 + 3 = 666.

It is not a de Polignac number, because 12165561243 - 2¹³ = 12165553051 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 12165561198 and 12165561207.

It is not an unprimeable number, because it can be changed into a prime (12165561203) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 9481480 + ... + 9482762.

It is an arithmetic number, because the mean of its divisors is an integer number (284487320).

Almost surely, 2^12165561243 is an apocalyptic number.

12165561243 is a deficient number, since it is larger than the sum of its proper divisors (8317525797).

12165561243 is a wasteful number, since it uses less digits than its factorization.

12165561243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1461 (or 1387 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

The spelling of 12165561243 in words is "twelve billion, one hundred sixty-five million, five hundred sixty-one thousand, two hundred forty-three".