16617121618 has 4 divisors (see below), whose sum is σ = 24925682430. Its totient is φ = 8308560808.

The previous prime is 16617121601. The next prime is 16617121649. The reversal of 16617121618 is 81612171661.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 81612171661 = 173 ⋅471746657.

It can be written as a sum of positive squares in only one way, i.e., 9436762449 + 7180359169 = 97143^2 + 84737^2 .

It is a super-2 number, since 2×16617121618² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4154280403 + ... + 4154280406.

Almost surely, 2^16617121618 is an apocalyptic number.

16617121618 is a deficient number, since it is larger than the sum of its proper divisors (8308560812).

16617121618 is an equidigital number, since it uses as much as digits as its factorization.

16617121618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8308560811.

The product of its digits is 24192, while the sum is 40.

The spelling of 16617121618 in words is "sixteen billion, six hundred seventeen million, one hundred twenty-one thousand, six hundred eighteen".