161886990 has 64 divisors (see below), whose sum is σ = 407592000. Its totient is φ = 41094144.

The previous prime is 161886953. The next prime is 161886997. The reversal of 161886990 is 99688161.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161886997) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 62236 + ... + 64784.

It is an arithmetic number, because the mean of its divisors is an integer number (6368625).

Almost surely, 2^161886990 is an apocalyptic number.

161886990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 161886990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (203796000).

161886990 is an abundant number, since it is smaller than the sum of its proper divisors (245705010).

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

161886990 is a wasteful number, since it uses less digits than its factorization.

161886990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2661.

The product of its (nonzero) digits is 186624, while the sum is 48.

The square root of 161886990 is about 12723.4818347809. The cubic root of 161886990 is about 545.0093873758.

The spelling of 161886990 in words is "one hundred sixty-one million, eight hundred eighty-six thousand, nine hundred ninety".