161606505600665 has 4 divisors (see below), whose sum is σ = 193927806720804. Its totient is φ = 129285204480528.

The previous prime is 161606505600619. The next prime is 161606505600671. The reversal of 161606505600665 is 566006505606161.

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 79130756429209 + 82475749171456 = 8895547^2 + 9081616^2 .

It is a cyclic number.

It is not a de Polignac number, because 161606505600665 - 2¹⁴ = 161606505584281 is a prime.

It is a super-2 number, since 2×161606505600665² (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, 16160650560062 + ... + 16160650560071.

It is an arithmetic number, because the mean of its divisors is an integer number (48481951680201).

Almost surely, 2^{161606505600665} is an apocalyptic number.

It is an amenable number.

161606505600665 is a deficient number, since it is larger than the sum of its proper divisors (32321301120139).

161606505600665 is an equidigital number, since it uses as much as digits as its factorization.

161606505600665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32321301120138.

The product of its (nonzero) digits is 5832000, while the sum is 53.

The spelling of 161606505600665 in words is "one hundred sixty-one trillion, six hundred six billion, five hundred five million, six hundred thousand, six hundred sixty-five".