166881861 has 6 divisors (see below), whose sum is σ = 241051590. Its totient is φ = 111254568.

The previous prime is 166881851. The next prime is 166881881. The reversal of 166881861 is 168188661.

166881861 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 only one way, i.e., 103917636 + 62964225 = 10194^2 + 7935^2 .

It is not a de Polignac number, because 166881861 - 2⁵ = 166881829 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166881811) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9271206 + ... + 9271223.

It is an arithmetic number, because the mean of its divisors is an integer number (40175265).

Almost surely, 2^166881861 is an apocalyptic number.

It is an amenable number.

166881861 is a deficient number, since it is larger than the sum of its proper divisors (74169729).

166881861 is a wasteful number, since it uses less digits than its factorization.

166881861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18542435 (or 18542432 counting only the distinct ones).

The product of its digits is 110592, while the sum is 45.

The square root of 166881861 is about 12918.2762394988. The cubic root of 166881861 is about 550.5579582948.

The spelling of 166881861 in words is "one hundred sixty-six million, eight hundred eighty-one thousand, eight hundred sixty-one".