161222618 has 4 divisors (see below), whose sum is σ = 241833930. Its totient is φ = 80611308.

The previous prime is 161222591. The next prime is 161222627. The reversal of 161222618 is 816222161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 816222161 = 103 ⋅7924487.

It can be written as a sum of positive squares in only one way, i.e., 94031809 + 67190809 = 9697^2 + 8197^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40305653 + ... + 40305656.

Almost surely, 2^161222618 is an apocalyptic number.

161222618 is a deficient number, since it is larger than the sum of its proper divisors (80611312).

161222618 is an equidigital number, since it uses as much as digits as its factorization.

161222618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80611311.

The product of its digits is 2304, while the sum is 29.

The square root of 161222618 is about 12697.3468882283. The cubic root of 161222618 is about 544.2628059947.

Adding to 161222618 its reverse (816222161), we get a palindrome (977444779).

The spelling of 161222618 in words is "one hundred sixty-one million, two hundred twenty-two thousand, six hundred eighteen".