166537888735661 has 32 divisors (see below), whose sum is σ = 178132604682240. Its totient is φ = 155231837031744.

The previous prime is 166537888735643. The next prime is 166537888735663.

166537888735661 is nontrivially palindromic in base 10.

It is a cyclic number.

It is not a de Polignac number, because 166537888735661 - 2³⁰ = 166536814993837 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166537888735663) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7921688996 + ... + 7921710018.

It is an arithmetic number, because the mean of its divisors is an integer number (5566643896320).

Almost surely, 2^{166537888735661} is an apocalyptic number.

It is an amenable number.

166537888735661 is a deficient number, since it is larger than the sum of its proper divisors (11594715946579).

166537888735661 is a wasteful number, since it uses less digits than its factorization.

166537888735661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28265.

The product of its digits is 7315660800, while the sum is 80.

The spelling of 166537888735661 in words is "one hundred sixty-six trillion, five hundred thirty-seven billion, eight hundred eighty-eight million, seven hundred thirty-five thousand, six hundred sixty-one".