166971217 has 4 divisors (see below), whose sum is σ = 190824256. Its totient is φ = 143118180.

The previous prime is 166971151. The next prime is 166971247. The reversal of 166971217 is 712179661.

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 not a de Polignac number, because 166971217 - 2⁷ = 166971089 is a prime.

It is a super-2 number, since 2×166971217² = 55758774612922178, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 166971217.

It is not an unprimeable number, because it can be changed into a prime (166971247) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11926509 + ... + 11926522.

It is an arithmetic number, because the mean of its divisors is an integer number (47706064).

Almost surely, 2^166971217 is an apocalyptic number.

It is an amenable number.

166971217 is a deficient number, since it is larger than the sum of its proper divisors (23853039).

166971217 is an equidigital number, since it uses as much as digits as its factorization.

166971217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23853038.

The product of its digits is 31752, while the sum is 40.

The square root of 166971217 is about 12921.7342876256. The cubic root of 166971217 is about 550.6562051997.

The spelling of 166971217 in words is "one hundred sixty-six million, nine hundred seventy-one thousand, two hundred seventeen".