166808217585 has 16 divisors (see below), whose sum is σ = 274106477376. Its totient is φ = 86559939648.

The previous prime is 166808217571. The next prime is 166808217593. The reversal of 166808217585 is 585712808661.

It is not a de Polignac number, because 166808217585 - 2²³ = 166799828977 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 150277119 + ... + 150278228.

It is an arithmetic number, because the mean of its divisors is an integer number (17131654836).

Almost surely, 2^166808217585 is an apocalyptic number.

166808217585 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

166808217585 is a deficient number, since it is larger than the sum of its proper divisors (107298259791).

166808217585 is a wasteful number, since it uses less digits than its factorization.

166808217585 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 300555392.

The product of its (nonzero) digits is 6451200, while the sum is 57.

The spelling of 166808217585 in words is "one hundred sixty-six billion, eight hundred eight million, two hundred seventeen thousand, five hundred eighty-five".