166907991749 has 4 divisors (see below), whose sum is σ = 170459225664. Its totient is φ = 163356757836.

The previous prime is 166907991743. The next prime is 166907991763. The reversal of 166907991749 is 947199709661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166907991749 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166907991743) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1775616887 + ... + 1775616980.

It is an arithmetic number, because the mean of its divisors is an integer number (42614806416).

Almost surely, 2^166907991749 is an apocalyptic number.

It is an amenable number.

166907991749 is a deficient number, since it is larger than the sum of its proper divisors (3551233915).

166907991749 is an equidigital number, since it uses as much as digits as its factorization.

166907991749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3551233914.

The product of its (nonzero) digits is 46294416, while the sum is 68.

The spelling of 166907991749 in words is "one hundred sixty-six billion, nine hundred seven million, nine hundred ninety-one thousand, seven hundred forty-nine".