161431873 has 4 divisors (see below), whose sum is σ = 161457748. Its totient is φ = 161406000.

The previous prime is 161431867. The next prime is 161431903. The reversal of 161431873 is 378134161.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 378134161 = 29 ⋅13039109.

It can be written as a sum of positive squares in 2 ways, for example, as 18939904 + 142491969 = 4352^2 + 11937^2 .

It is a cyclic number.

It is not a de Polignac number, because 161431873 - 2⁵ = 161431841 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161437873) 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, 2815 + ... + 18187.

It is an arithmetic number, because the mean of its divisors is an integer number (40364437).

Almost surely, 2^161431873 is an apocalyptic number.

It is an amenable number.

161431873 is a deficient number, since it is larger than the sum of its proper divisors (25875).

161431873 is a wasteful number, since it uses less digits than its factorization.

161431873 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25874.

The product of its digits is 12096, while the sum is 34.

The square root of 161431873 is about 12705.5843234383. The cubic root of 161431873 is about 544.4981751112.

The spelling of 161431873 in words is "one hundred sixty-one million, four hundred thirty-one thousand, eight hundred seventy-three".