161217618 has 32 divisors (see below), whose sum is σ = 329313600. Its totient is φ = 52600896.

The previous prime is 161217607. The next prime is 161217631. The reversal of 161217618 is 816712161.

It is a happy number.

It is a super-2 number, since 2×161217618² = 51982240707187848, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 94380 + ... + 96072.

It is an arithmetic number, because the mean of its divisors is an integer number (10291050).

Almost surely, 2^161217618 is an apocalyptic number.

161217618 is an abundant number, since it is smaller than the sum of its proper divisors (168095982).

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

161217618 is a wasteful number, since it uses less digits than its factorization.

161217618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2026.

The product of its digits is 4032, while the sum is 33.

The square root of 161217618 is about 12697.1499951761. The cubic root of 161217618 is about 544.2571795257.

Adding to 161217618 its reverse (816712161), we get a palindrome (977929779).

The spelling of 161217618 in words is "one hundred sixty-one million, two hundred seventeen thousand, six hundred eighteen".