161891136 has 280 divisors, whose sum is σ = 557637696. Its totient is φ = 45895680.

The previous prime is 161891129. The next prime is 161891141. The reversal of 161891136 is 631198161.

It is a happy number.

161891136 is a `hidden beast` number, since 1 + 618 + 9 + 1 + 1 + 36 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 161891136.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 969325 + ... + 969491.

Almost surely, 2^161891136 is an apocalyptic number.

161891136 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161891136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (278818848).

161891136 is an abundant number, since it is smaller than the sum of its proper divisors (395746560).

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

161891136 is a wasteful number, since it uses less digits than its factorization.

161891136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219 (or 200 counting only the distinct ones).

The product of its digits is 7776, while the sum is 36.

The square root of 161891136 is about 12723.6447608380. The cubic root of 161891136 is about 545.0140399828.

The spelling of 161891136 in words is "one hundred sixty-one million, eight hundred ninety-one thousand, one hundred thirty-six".