166561110681 has 32 divisors (see below), whose sum is σ = 269052795648. Its totient is φ = 89473904640.

The previous prime is 166561110679. The next prime is 166561110689. The reversal of 166561110681 is 186011165661.

It is not a de Polignac number, because 166561110681 - 2¹ = 166561110679 is a prime.

It is a super-2 number, since 2×166561110681² (a number of 23 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (166561110689) 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, 31041 + ... + 578001.

It is an arithmetic number, because the mean of its divisors is an integer number (8407899864).

Almost surely, 2^166561110681 is an apocalyptic number.

It is an amenable number.

166561110681 is a deficient number, since it is larger than the sum of its proper divisors (102491684967).

166561110681 is a wasteful number, since it uses less digits than its factorization.

166561110681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 547841.

The product of its (nonzero) digits is 51840, while the sum is 42.

The spelling of 166561110681 in words is "one hundred sixty-six billion, five hundred sixty-one million, one hundred ten thousand, six hundred eighty-one".