161891856 has 240 divisors, whose sum is σ = 557107200. Its totient is φ = 42861312.

The previous prime is 161891797. The next prime is 161891879. The reversal of 161891856 is 658198161.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1512955 + ... + 1513061.

It is an arithmetic number, because the mean of its divisors is an integer number (2321280).

Almost surely, 2^161891856 is an apocalyptic number.

161891856 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161891856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (278553600).

161891856 is an abundant number, since it is smaller than the sum of its proper divisors (395215344).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161891856 is a wasteful number, since it uses less digits than its factorization.

161891856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226 (or 217 counting only the distinct ones).

The product of its digits is 103680, while the sum is 45.

The square root of 161891856 is about 12723.6730545861. The cubic root of 161891856 is about 545.0148479528.

The spelling of 161891856 in words is "one hundred sixty-one million, eight hundred ninety-one thousand, eight hundred fifty-six".