161565505023 has 16 divisors (see below), whose sum is σ = 232017228800. Its totient is φ = 99413897184.

The previous prime is 161565505007. The next prime is 161565505109. The reversal of 161565505023 is 320505565161.

It is not a de Polignac number, because 161565505023 - 2⁴ = 161565505007 is a prime.

It is a super-3 number, since 3×161565505023³ (a number of 35 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161565505223) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 133590 + ... + 583932.

It is an arithmetic number, because the mean of its divisors is an integer number (14501076800).

Almost surely, 2^161565505023 is an apocalyptic number.

161565505023 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

161565505023 is a deficient number, since it is larger than the sum of its proper divisors (70451723777).

161565505023 is a wasteful number, since it uses less digits than its factorization.

161565505023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 459558.

The product of its (nonzero) digits is 135000, while the sum is 39.

The spelling of 161565505023 in words is "one hundred sixty-one billion, five hundred sixty-five million, five hundred five thousand, twenty-three".