166661511057 has 6 divisors (see below), whose sum is σ = 240733293762. Its totient is φ = 111107674032.

The previous prime is 166661511017. The next prime is 166661511061. The reversal of 166661511057 is 750115166661.

It can be written as a sum of positive squares in only one way, i.e., 166628056401 + 33454656 = 408201^2 + 5784^2 .

It is not a de Polignac number, because 166661511057 - 2³⁴ = 149481641873 is a prime.

It is not an unprimeable number, because it can be changed into a prime (166661511017) 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, 9258972828 + ... + 9258972845.

It is an arithmetic number, because the mean of its divisors is an integer number (40122215627).

Almost surely, 2^166661511057 is an apocalyptic number.

It is an amenable number.

166661511057 is a deficient number, since it is larger than the sum of its proper divisors (74071782705).

166661511057 is a wasteful number, since it uses less digits than its factorization.

166661511057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18517945679 (or 18517945676 counting only the distinct ones).

The product of its (nonzero) digits is 226800, while the sum is 45.

The spelling of 166661511057 in words is "one hundred sixty-six billion, six hundred sixty-one million, five hundred eleven thousand, fifty-seven".