161281577231 has 4 divisors (see below), whose sum is σ = 164324625912. Its totient is φ = 158238528552.

The previous prime is 161281577207. The next prime is 161281577267. The reversal of 161281577231 is 132775182161.

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 161281577231 - 2⁶ = 161281577167 is a prime.

It is a super-2 number, since 2×161281577231² (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 (161281577291) 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, 1521524261 + ... + 1521524366.

It is an arithmetic number, because the mean of its divisors is an integer number (41081156478).

Almost surely, 2^161281577231 is an apocalyptic number.

161281577231 is a deficient number, since it is larger than the sum of its proper divisors (3043048681).

161281577231 is an equidigital number, since it uses as much as digits as its factorization.

161281577231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3043048680.

The product of its digits is 141120, while the sum is 44.

The spelling of 161281577231 in words is "one hundred sixty-one billion, two hundred eighty-one million, five hundred seventy-seven thousand, two hundred thirty-one".