165561235232665 has 4 divisors (see below), whose sum is σ = 198673482279204. Its totient is φ = 132448988186128.

The previous prime is 165561235232651. The next prime is 165561235232671. The reversal of 165561235232665 is 566232532165561.

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 39255374998921 + 126305860233744 = 6265411^2 + 11238588^2 .

It is a cyclic number.

It is not a de Polignac number, because 165561235232665 - 2¹¹ = 165561235230617 is a prime.

It is a super-2 number, since 2×165561235232665² (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, 16556123523262 + ... + 16556123523271.

It is an arithmetic number, because the mean of its divisors is an integer number (49668370569801).

Almost surely, 2^{165561235232665} is an apocalyptic number.

It is an amenable number.

165561235232665 is a deficient number, since it is larger than the sum of its proper divisors (33112247046539).

165561235232665 is an equidigital number, since it uses as much as digits as its factorization.

165561235232665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33112247046538.

The product of its digits is 58320000, while the sum is 58.

The spelling of 165561235232665 in words is "one hundred sixty-five trillion, five hundred sixty-one billion, two hundred thirty-five million, two hundred thirty-two thousand, six hundred sixty-five".