161556143523 has 4 divisors (see below), whose sum is σ = 215408191368. Its totient is φ = 107704095680.

The previous prime is 161556143513. The next prime is 161556143533. The reversal of 161556143523 is 325341655161.

It is a happy number.

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

It is an interprime number because it is at equal distance from previous prime (161556143513) and next prime (161556143533).

It is a cyclic number.

It is not a de Polignac number, because 161556143523 - 2⁵ = 161556143491 is a prime.

It is a super-2 number, since 2×161556143523² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161556143513) 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, 26926023918 + ... + 26926023923.

It is an arithmetic number, because the mean of its divisors is an integer number (53852047842).

Almost surely, 2^161556143523 is an apocalyptic number.

161556143523 is a deficient number, since it is larger than the sum of its proper divisors (53852047845).

161556143523 is an equidigital number, since it uses as much as digits as its factorization.

161556143523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53852047844.

The product of its digits is 324000, while the sum is 42.

Adding to 161556143523 its reverse (325341655161), we get a palindrome (486897798684).

The spelling of 161556143523 in words is "one hundred sixty-one billion, five hundred fifty-six million, one hundred forty-three thousand, five hundred twenty-three".