161131542 has 64 divisors (see below), whose sum is σ = 400909824. Its totient is φ = 42416640.

The previous prime is 161131519. The next prime is 161131543. The reversal of 161131542 is 245131161.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161131543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9063 + ... + 20109.

It is an arithmetic number, because the mean of its divisors is an integer number (6264216).

Almost surely, 2^161131542 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161131542, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (200454912).

161131542 is an abundant number, since it is smaller than the sum of its proper divisors (239778282).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161131542 is a wasteful number, since it uses less digits than its factorization.

161131542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11093.

The product of its digits is 720, while the sum is 24.

The square root of 161131542 is about 12693.7599630685. The cubic root of 161131542 is about 544.1603004925.

It can be divided in two parts, 1611 and 31542, that added together give a triangular number (33153 = T₂₅₇).

The spelling of 161131542 in words is "one hundred sixty-one million, one hundred thirty-one thousand, five hundred forty-two".