166211917 has 4 divisors (see below), whose sum is σ = 166253920. Its totient is φ = 166169916.

The previous prime is 166211887. The next prime is 166211939. The reversal of 166211917 is 719112661.

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, and also an emirpimes, since its reverse is a distinct semiprime: 719112661 = 8641 ⋅83221.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166211917 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 (166211957) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14367 + ... + 23212.

It is an arithmetic number, because the mean of its divisors is an integer number (41563480).

Almost surely, 2^166211917 is an apocalyptic number.

It is an amenable number.

166211917 is a deficient number, since it is larger than the sum of its proper divisors (42003).

166211917 is an equidigital number, since it uses as much as digits as its factorization.

166211917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42002.

The product of its digits is 4536, while the sum is 34.

The square root of 166211917 is about 12892.3200782481. The cubic root of 166211917 is about 549.8202354662.

The spelling of 166211917 in words is "one hundred sixty-six million, two hundred eleven thousand, nine hundred seventeen".