2216611665 has 24 divisors (see below), whose sum is σ = 3974616360. Its totient is φ = 1141426944.

The previous prime is 2216611561. The next prime is 2216611681. The reversal of 2216611665 is 5661166122.

2216611665 is a `hidden beast` number, since 22 + 16 + 611 + 6 + 6 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 164249856 + 2052361809 = 12816^2 + 45303^2 .

It is not a de Polignac number, because 2216611665 - 2¹⁴ = 2216595281 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 847972 + ... + 850581.

It is an arithmetic number, because the mean of its divisors is an integer number (165609015).

Almost surely, 2^2216611665 is an apocalyptic number.

It is an amenable number.

2216611665 is a deficient number, since it is larger than the sum of its proper divisors (1758004695).

2216611665 is a wasteful number, since it uses less digits than its factorization.

2216611665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1698593 (or 1698590 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 2216611665 is about 47080.9055244268. The cubic root of 2216611665 is about 1303.8567253933.

Adding to 2216611665 its reverse (5661166122), we get a palindrome (7877777787).

The spelling of 2216611665 in words is "two billion, two hundred sixteen million, six hundred eleven thousand, six hundred sixty-five".