161881650 has 144 divisors (see below), whose sum is σ = 526466304. Its totient is φ = 34813440.

The previous prime is 161881649. The next prime is 161881669. The reversal of 161881650 is 56188161.

It is a Curzon number.

It is an unprimeable number.

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 71 ways as a sum of consecutive naturals, for example, 52039 + ... + 55061.

It is an arithmetic number, because the mean of its divisors is an integer number (3656016).

Almost surely, 2^161881650 is an apocalyptic number.

161881650 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 161881650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (263233152).

161881650 is an abundant number, since it is smaller than the sum of its proper divisors (364584654).

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

161881650 is a wasteful number, since it uses less digits than its factorization.

161881650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3065 (or 3057 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 36.

The square root of 161881650 is about 12723.2719848316. The cubic root of 161881650 is about 545.0033947548.

The spelling of 161881650 in words is "one hundred sixty-one million, eight hundred eighty-one thousand, six hundred fifty".