166501561161 has 16 divisors (see below), whose sum is σ = 239179625216. Its totient is φ = 102419444736.

The previous prime is 166501561157. The next prime is 166501561183. The reversal of 166501561161 is 161165105661.

It is not a de Polignac number, because 166501561161 - 2² = 166501561157 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166501561361) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 802840 + ... + 988713.

It is an arithmetic number, because the mean of its divisors is an integer number (14948726576).

Almost surely, 2^166501561161 is an apocalyptic number.

It is an amenable number.

166501561161 is a deficient number, since it is larger than the sum of its proper divisors (72678064055).

166501561161 is a wasteful number, since it uses less digits than its factorization.

166501561161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1793952.

The product of its (nonzero) digits is 32400, while the sum is 39.

The spelling of 166501561161 in words is "one hundred sixty-six billion, five hundred one million, five hundred sixty-one thousand, one hundred sixty-one".