161811878 has 16 divisors (see below), whose sum is σ = 257322624. Its totient is φ = 76178880.

The previous prime is 161811857. The next prime is 161811889. The reversal of 161811878 is 878118161.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32975 + ... + 37562.

It is an arithmetic number, because the mean of its divisors is an integer number (16082664).

Almost surely, 2^161811878 is an apocalyptic number.

161811878 is a deficient number, since it is larger than the sum of its proper divisors (95510746).

161811878 is a wasteful number, since it uses less digits than its factorization.

161811878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70607.

The product of its digits is 21504, while the sum is 41.

The square root of 161811878 is about 12720.5297845648. The cubic root of 161811878 is about 544.9250835497.

The spelling of 161811878 in words is "one hundred sixty-one million, eight hundred eleven thousand, eight hundred seventy-eight".