161891855 has 8 divisors (see below), whose sum is σ = 194367264. Its totient is φ = 129448800.

The previous prime is 161891797. The next prime is 161891879. The reversal of 161891855 is 558198161.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 161891855 - 2¹⁰ = 161890831 is a prime.

It is a Duffinian number.

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, 4790 + ... + 18620.

It is an arithmetic number, because the mean of its divisors is an integer number (24295908).

Almost surely, 2^161891855 is an apocalyptic number.

161891855 is a deficient number, since it is larger than the sum of its proper divisors (32475409).

161891855 is a wasteful number, since it uses less digits than its factorization.

161891855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16177.

The product of its digits is 86400, while the sum is 44.

The square root of 161891855 is about 12723.6730152893. The cubic root of 161891855 is about 545.0148468306.

The spelling of 161891855 in words is "one hundred sixty-one million, eight hundred ninety-one thousand, eight hundred fifty-five".