171998681 has 16 divisors (see below), whose sum is σ = 184082640. Its totient is φ = 160392960.

The previous prime is 171998663. The next prime is 171998683. The reversal of 171998681 is 186899171.

171998681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 5175625 + 166823056 = 2275^2 + 12916^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-171998681 is a prime.

It is a super-2 number, since 2×171998681² = 59167092531479522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (171998683) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 167951 + ... + 168971.

It is an arithmetic number, because the mean of its divisors is an integer number (11505165).

Almost surely, 2^171998681 is an apocalyptic number.

It is an amenable number.

171998681 is a deficient number, since it is larger than the sum of its proper divisors (12083959).

171998681 is a wasteful number, since it uses less digits than its factorization.

171998681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1244.

The product of its digits is 217728, while the sum is 50.

The square root of 171998681 is about 13114.8267621040. The cubic root of 171998681 is about 556.1283550687.

The spelling of 171998681 in words is "one hundred seventy-one million, nine hundred ninety-eight thousand, six hundred eighty-one".