166871857217 has 32 divisors (see below), whose sum is σ = 200177308800. Its totient is φ = 137602741248.

The previous prime is 166871857189. The next prime is 166871857223. The reversal of 166871857217 is 712758178661.

It is a happy number.

It is not a de Polignac number, because 166871857217 - 2⁶ = 166871857153 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (59).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166871850217) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 157478 + ... + 598784.

It is an arithmetic number, because the mean of its divisors is an integer number (6255540900).

Almost surely, 2^166871857217 is an apocalyptic number.

166871857217 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

166871857217 is a deficient number, since it is larger than the sum of its proper divisors (33305451583).

166871857217 is a wasteful number, since it uses less digits than its factorization.

166871857217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 441425.

The product of its digits is 7902720, while the sum is 59.

The spelling of 166871857217 in words is "one hundred sixty-six billion, eight hundred seventy-one million, eight hundred fifty-seven thousand, two hundred seventeen".