161857187 has 16 divisors (see below), whose sum is σ = 180610560. Its totient is φ = 144262272.

The previous prime is 161857183. The next prime is 161857229. The reversal of 161857187 is 781758161.

It is not a de Polignac number, because 161857187 - 2² = 161857183 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161857183) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38264 + ... + 42282.

It is an arithmetic number, because the mean of its divisors is an integer number (11288160).

Almost surely, 2^161857187 is an apocalyptic number.

161857187 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

161857187 is a deficient number, since it is larger than the sum of its proper divisors (18753373).

161857187 is a wasteful number, since it uses less digits than its factorization.

161857187 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4162.

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

The square root of 161857187 is about 12722.3105998871. The cubic root of 161857187 is about 544.9759403569.

The spelling of 161857187 in words is "one hundred sixty-one million, eight hundred fifty-seven thousand, one hundred eighty-seven".