166236881 has 4 divisors (see below), whose sum is σ = 167762100. Its totient is φ = 164711664.

The previous prime is 166236877. The next prime is 166236907. The reversal of 166236881 is 188632661.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 129026881 + 37210000 = 11359^2 + 6100^2 .

It is a cyclic number.

It is not a de Polignac number, because 166236881 - 2² = 166236877 is a prime.

It is a super-2 number, since 2×166236881² = 55269401209216322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166236821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 762446 + ... + 762663.

It is an arithmetic number, because the mean of its divisors is an integer number (41940525).

Almost surely, 2^166236881 is an apocalyptic number.

It is an amenable number.

166236881 is a deficient number, since it is larger than the sum of its proper divisors (1525219).

166236881 is a wasteful number, since it uses less digits than its factorization.

166236881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1525218.

The product of its digits is 82944, while the sum is 41.

The square root of 166236881 is about 12893.2882151917. The cubic root of 166236881 is about 549.8477606190.

The spelling of 166236881 in words is "one hundred sixty-six million, two hundred thirty-six thousand, eight hundred eighty-one".