12166731521 has 16 divisors (see below), whose sum is σ = 14650281984. Its totient is φ = 9878348304.

The previous prime is 12166731517. The next prime is 12166731539. The reversal of 12166731521 is 12513766121.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 12166731521 - 2² = 12166731517 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12166731121) 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, 350261 + ... + 383426.

It is an arithmetic number, because the mean of its divisors is an integer number (915642624).

Almost surely, 2^12166731521 is an apocalyptic number.

It is an amenable number.

12166731521 is a deficient number, since it is larger than the sum of its proper divisors (2483550463).

12166731521 is a wasteful number, since it uses less digits than its factorization.

12166731521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 733820.

The product of its digits is 15120, while the sum is 35.

The spelling of 12166731521 in words is "twelve billion, one hundred sixty-six million, seven hundred thirty-one thousand, five hundred twenty-one".