161878573 has 4 divisors (see below), whose sum is σ = 171400860. Its totient is φ = 152356288.

The previous prime is 161878543. The next prime is 161878579. The reversal of 161878573 is 375878161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 375878161 = 547 ⋅687163.

It can be written as a sum of positive squares in 2 ways, for example, as 125372809 + 36505764 = 11197^2 + 6042^2 .

It is a cyclic number.

It is not a de Polignac number, because 161878573 - 2⁹ = 161878061 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161878579) 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, 4761118 + ... + 4761151.

It is an arithmetic number, because the mean of its divisors is an integer number (42850215).

Almost surely, 2^161878573 is an apocalyptic number.

It is an amenable number.

161878573 is a deficient number, since it is larger than the sum of its proper divisors (9522287).

161878573 is an equidigital number, since it uses as much as digits as its factorization.

161878573 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9522286.

The product of its digits is 282240, while the sum is 46.

The square root of 161878573 is about 12723.1510641036. The cubic root of 161878573 is about 544.9999416435. Note that the first 4 decimals are identical.

The spelling of 161878573 in words is "one hundred sixty-one million, eight hundred seventy-eight thousand, five hundred seventy-three".