12166551 has 16 divisors (see below), whose sum is σ = 18079200. Its totient is φ = 8086464.

The previous prime is 12166547. The next prime is 12166579. The reversal of 12166551 is 15566121.

It is a happy number.

12166551 is a `hidden beast` number, since 1 + 2 + 1 + 6 + 655 + 1 = 666.

It is not a de Polignac number, because 12166551 - 2² = 12166547 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12166501) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14635 + ... + 15443.

It is an arithmetic number, because the mean of its divisors is an integer number (1129950).

Almost surely, 2^12166551 is an apocalyptic number.

12166551 is a deficient number, since it is larger than the sum of its proper divisors (5912649).

12166551 is an equidigital number, since it uses as much as digits as its factorization.

12166551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1375 (or 1369 counting only the distinct ones).

The product of its digits is 1800, while the sum is 27.

The square root of 12166551 is about 3488.0583424020. The cubic root of 12166551 is about 229.9971707276.

The spelling of 12166551 in words is "twelve million, one hundred sixty-six thousand, five hundred fifty-one".