166601800825 has 6 divisors (see below), whose sum is σ = 206586233054. Its totient is φ = 133281440640.

The previous prime is 166601800823. The next prime is 166601800877. The reversal of 166601800825 is 528008106661.

It can be written as a sum of positive squares in 3 ways, for example, as 42029510121 + 124572290704 = 205011^2 + 352948^2 .

It is not a de Polignac number, because 166601800825 - 2¹ = 166601800823 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166601800823) 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, 3332035992 + ... + 3332036041.

Almost surely, 2^166601800825 is an apocalyptic number.

It is an amenable number.

166601800825 is a deficient number, since it is larger than the sum of its proper divisors (39984432229).

166601800825 is an equidigital number, since it uses as much as digits as its factorization.

166601800825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6664072043 (or 6664072038 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 43.

The spelling of 166601800825 in words is "one hundred sixty-six billion, six hundred one million, eight hundred thousand, eight hundred twenty-five".