161187578 has 4 divisors (see below), whose sum is σ = 241781370. Its totient is φ = 80593788.

The previous prime is 161187553. The next prime is 161187589. The reversal of 161187578 is 875781161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 875781161 = 5897 ⋅148513.

It can be written as a sum of positive squares in only one way, i.e., 146724769 + 14462809 = 12113^2 + 3803^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40296893 + ... + 40296896.

Almost surely, 2^161187578 is an apocalyptic number.

161187578 is a deficient number, since it is larger than the sum of its proper divisors (80593792).

161187578 is an equidigital number, since it uses as much as digits as its factorization.

161187578 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80593791.

The product of its digits is 94080, while the sum is 44.

The square root of 161187578 is about 12695.9669974366. The cubic root of 161187578 is about 544.2233732510.

The spelling of 161187578 in words is "one hundred sixty-one million, one hundred eighty-seven thousand, five hundred seventy-eight".