161105661 has 12 divisors (see below), whose sum is σ = 232818300. Its totient is φ = 107352960.

The previous prime is 161105657. The next prime is 161105663. The reversal of 161105661 is 166501161.

It can be written as a sum of positive squares in 2 ways, for example, as 88003161 + 73102500 = 9381^2 + 8550^2 .

It is not a de Polignac number, because 161105661 - 2² = 161105657 is a prime.

It is a super-5 number, since 5×161105661⁵ (a number of 42 digits) contains 55555 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161105663) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 34231 + ... + 38651.

It is an arithmetic number, because the mean of its divisors is an integer number (19401525).

Almost surely, 2^161105661 is an apocalyptic number.

It is an amenable number.

161105661 is a deficient number, since it is larger than the sum of its proper divisors (71712639).

161105661 is a wasteful number, since it uses less digits than its factorization.

161105661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8476 (or 8473 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 27.

The square root of 161105661 is about 12692.7404842296. The cubic root of 161105661 is about 544.1311645317.

The spelling of 161105661 in words is "one hundred sixty-one million, one hundred five thousand, six hundred sixty-one".