161565505013 has 4 divisors (see below), whose sum is σ = 176253278208. Its totient is φ = 146877731820.

The previous prime is 161565505007. The next prime is 161565505109. The reversal of 161565505013 is 310505565161.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 161565505013 - 2¹⁰ = 161565503989 is a prime.

It is a super-2 number, since 2×161565505013² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161565505513) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7343886581 + ... + 7343886602.

It is an arithmetic number, because the mean of its divisors is an integer number (44063319552).

Almost surely, 2^161565505013 is an apocalyptic number.

It is an amenable number.

161565505013 is a deficient number, since it is larger than the sum of its proper divisors (14687773195).

161565505013 is a wasteful number, since it uses less digits than its factorization.

161565505013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14687773194.

The product of its (nonzero) digits is 67500, while the sum is 38.

The spelling of 161565505013 in words is "one hundred sixty-one billion, five hundred sixty-five million, five hundred five thousand, thirteen".