161881749 has 12 divisors (see below), whose sum is σ = 234040716. Its totient is φ = 107823552.

The previous prime is 161881747. The next prime is 161881757. The reversal of 161881749 is 947188161.

It is a happy number.

161881749 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 35319249 + 126562500 = 5943^2 + 11250^2 .

It is not a de Polignac number, because 161881749 - 2¹ = 161881747 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161881747) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3199 + ... + 18275.

It is an arithmetic number, because the mean of its divisors is an integer number (19503393).

Almost surely, 2^161881749 is an apocalyptic number.

It is an amenable number.

161881749 is a deficient number, since it is larger than the sum of its proper divisors (72158967).

161881749 is a wasteful number, since it uses less digits than its factorization.

161881749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16276 (or 16273 counting only the distinct ones).

The product of its digits is 96768, while the sum is 45.

The square root of 161881749 is about 12723.2758753397. The cubic root of 161881749 is about 545.0035058552.

The spelling of 161881749 in words is "one hundred sixty-one million, eight hundred eighty-one thousand, seven hundred forty-nine".