161581112 has 64 divisors (see below), whose sum is σ = 385827840. Its totient is φ = 61603200.

The previous prime is 161581087. The next prime is 161581129. The reversal of 161581112 is 211185161.

It is a super-2 number, since 2×161581112² = 52216911510313088, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26162 + ... + 31742.

It is an arithmetic number, because the mean of its divisors is an integer number (6028560).

Almost surely, 2^161581112 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161581112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (192913920).

161581112 is an abundant number, since it is smaller than the sum of its proper divisors (224246728).

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

161581112 is a wasteful number, since it uses less digits than its factorization.

161581112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5652 (or 5648 counting only the distinct ones).

The product of its digits is 480, while the sum is 26.

The square root of 161581112 is about 12711.4559354938. The cubic root of 161581112 is about 544.6659142604.

The spelling of 161581112 in words is "one hundred sixty-one million, five hundred eighty-one thousand, one hundred twelve".