161890 has 8 divisors (see below), whose sum is σ = 291420. Its totient is φ = 64752.

The previous prime is 161881. The next prime is 161911. The reversal of 161890 is 98161.

It can be written as a sum of positive squares in 2 ways, for example, as 160801 + 1089 = 401^2 + 33^2 .

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

It is an alternating number because its digits alternate between odd and even.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8085 + ... + 8104.

2¹⁶¹⁸⁹⁰ is an apocalyptic number.

161890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

161890 is a deficient number, since it is larger than the sum of its proper divisors (129530).

161890 is a wasteful number, since it uses less digits than its factorization.

161890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16196.

The product of its (nonzero) digits is 432, while the sum is 25.

The square root of 161890 is about 402.3555641469. The cubic root of 161890 is about 54.5012765181.

The spelling of 161890 in words is "one hundred sixty-one thousand, eight hundred ninety".