2215610665 has 4 divisors (see below), whose sum is σ = 2658732804. Its totient is φ = 1772488528.

The previous prime is 2215610609. The next prime is 2215610713. The reversal of 2215610665 is 5660165122.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5660165122 = 2 ⋅2830082561.

It can be written as a sum of positive squares in 2 ways, for example, as 1739890944 + 475719721 = 41712^2 + 21811^2 .

It is a cyclic number.

It is not a de Polignac number, because 2215610665 - 2¹¹ = 2215608617 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2215610665.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 221561062 + ... + 221561071.

It is an arithmetic number, because the mean of its divisors is an integer number (664683201).

Almost surely, 2^2215610665 is an apocalyptic number.

It is an amenable number.

2215610665 is a deficient number, since it is larger than the sum of its proper divisors (443122139).

2215610665 is an equidigital number, since it uses as much as digits as its factorization.

2215610665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 443122138.

The product of its (nonzero) digits is 21600, while the sum is 34.

The square root of 2215610665 is about 47070.2736873284. The cubic root of 2215610665 is about 1303.6604262222.

Adding to 2215610665 its reverse (5660165122), we get a palindrome (7875775787).

The spelling of 2215610665 in words is "two billion, two hundred fifteen million, six hundred ten thousand, six hundred sixty-five".