161611101566065 has 4 divisors (see below), whose sum is σ = 193933321879284. Its totient is φ = 129288881252848.

The previous prime is 161611101566051. The next prime is 161611101566087. The reversal of 161611101566065 is 560665101116161.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 128066884088896 + 33544217477169 = 11316664^2 + 5791737^2 .

It is a cyclic number.

It is not a de Polignac number, because 161611101566065 - 2²¹ = 161611099468913 is a prime.

It is a super-2 number, since 2×161611101566065² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16161110156602 + ... + 16161110156611.

It is an arithmetic number, because the mean of its divisors is an integer number (48483330469821).

Almost surely, 2^{161611101566065} is an apocalyptic number.

It is an amenable number.

161611101566065 is a deficient number, since it is larger than the sum of its proper divisors (32322220313219).

161611101566065 is an equidigital number, since it uses as much as digits as its factorization.

161611101566065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32322220313218.

The product of its (nonzero) digits is 194400, while the sum is 46.

The spelling of 161611101566065 in words is "one hundred sixty-one trillion, six hundred eleven billion, one hundred one million, five hundred sixty-six thousand, sixty-five".