161601566116651 has 4 divisors (see below), whose sum is σ = 161603819699904. Its totient is φ = 161599312533400.

The previous prime is 161601566116649. The next prime is 161601566116709. The reversal of 161601566116651 is 156611665106161.

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

It is a cyclic number.

It is not a de Polignac number, because 161601566116651 - 2¹ = 161601566116649 is a prime.

It is a super-2 number, since 2×161601566116651² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161601566116621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1126684060 + ... + 1126827481.

It is an arithmetic number, because the mean of its divisors is an integer number (40400954924976).

Almost surely, 2^{161601566116651} is an apocalyptic number.

161601566116651 is a deficient number, since it is larger than the sum of its proper divisors (2253583253).

161601566116651 is an equidigital number, since it uses as much as digits as its factorization.

161601566116651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2253583252.

The product of its (nonzero) digits is 1166400, while the sum is 52.

The spelling of 161601566116651 in words is "one hundred sixty-one trillion, six hundred one billion, five hundred sixty-six million, one hundred sixteen thousand, six hundred fifty-one".