161698 has 4 divisors (see below), whose sum is σ = 242550. Its totient is φ = 80848.

The previous prime is 161683. The next prime is 161717. The reversal of 161698 is 896161.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 131769 + 29929 = 363^2 + 173^2 .

It is a super-2 number, since 2×161698² = 52292486408, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

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 as a sum of consecutive naturals, namely, 40423 + ... + 40426.

2¹⁶¹⁶⁹⁸ is an apocalyptic number.

161698 is a deficient number, since it is larger than the sum of its proper divisors (80852).

161698 is an equidigital number, since it uses as much as digits as its factorization.

161698 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80851.

The product of its digits is 2592, while the sum is 31.

The square root of 161698 is about 402.1168984263. The cubic root of 161698 is about 54.4797219962.

The spelling of 161698 in words is "one hundred sixty-one thousand, six hundred ninety-eight".