161556729941 has 4 divisors (see below), whose sum is σ = 161557595232. Its totient is φ = 161555864652.

The previous prime is 161556729931. The next prime is 161556729977. The reversal of 161556729941 is 149927655161.

It is a happy number.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 161556729941 - 2¹⁸ = 161556467797 is a prime.

It is a super-2 number, since 2×161556729941² (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 (161556729931) 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, 23795 + ... + 568928.

It is an arithmetic number, because the mean of its divisors is an integer number (40389398808).

Almost surely, 2^161556729941 is an apocalyptic number.

It is an amenable number.

161556729941 is a deficient number, since it is larger than the sum of its proper divisors (865291).

161556729941 is an equidigital number, since it uses as much as digits as its factorization.

161556729941 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 865290.

The product of its digits is 4082400, while the sum is 56.

The spelling of 161556729941 in words is "one hundred sixty-one billion, five hundred fifty-six million, seven hundred twenty-nine thousand, nine hundred forty-one".