161881123 has 4 divisors (see below), whose sum is σ = 171403560. Its totient is φ = 152358688.

The previous prime is 161881087. The next prime is 161881141. The reversal of 161881123 is 321188161.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 161881123 - 2²¹ = 159783971 is a prime.

It is a super-2 number, since 2×161881123² = 52410995967482258, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161888123) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4761193 + ... + 4761226.

It is an arithmetic number, because the mean of its divisors is an integer number (42850890).

Almost surely, 2^161881123 is an apocalyptic number.

161881123 is a deficient number, since it is larger than the sum of its proper divisors (9522437).

161881123 is an equidigital number, since it uses as much as digits as its factorization.

161881123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9522436.

The product of its digits is 2304, while the sum is 31.

The square root of 161881123 is about 12723.2512747332. The cubic root of 161881123 is about 545.0028033411.

The spelling of 161881123 in words is "one hundred sixty-one million, eight hundred eighty-one thousand, one hundred twenty-three".