161618 has 4 divisors (see below), whose sum is σ = 242430. Its totient is φ = 80808.

The previous prime is 161611. The next prime is 161627. The reversal of 161618 is 816161.

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., 120409 + 41209 = 347^2 + 203^2 .

It is a super-2 number, since 2×161618² = 52240755848, which contains 22 as substring.

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

It is a junction number, because it is equal to n+sod(n) for n = 161593 and 161602.

It is not an unprimeable number, because it can be changed into a prime (161611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40403 + ... + 40406.

2¹⁶¹⁶¹⁸ is an apocalyptic number.

161618 is a deficient number, since it is larger than the sum of its proper divisors (80812).

161618 is an equidigital number, since it uses as much as digits as its factorization.

161618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80811.

The product of its digits is 288, while the sum is 23.

The square root of 161618 is about 402.0174125582. The cubic root of 161618 is about 54.4707359095.

Adding to 161618 its reverse (816161), we get a palindrome (977779).

The spelling of 161618 in words is "one hundred sixty-one thousand, six hundred eighteen".