111215201665 has 4 divisors (see below), whose sum is σ = 133458242004. Its totient is φ = 88972161328.

The previous prime is 111215201663. The next prime is 111215201683. The reversal of 111215201665 is 566102512111.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 566102512111 = 61 ⋅9280369051.

It can be written as a sum of positive squares in 2 ways, for example, as 34153996864 + 77061204801 = 184808^2 + 277599^2 .

It is a cyclic number.

It is not a de Polignac number, because 111215201665 - 2¹ = 111215201663 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (111215201663) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11121520162 + ... + 11121520171.

It is an arithmetic number, because the mean of its divisors is an integer number (33364560501).

Almost surely, 2^111215201665 is an apocalyptic number.

It is an amenable number.

111215201665 is a deficient number, since it is larger than the sum of its proper divisors (22243040339).

111215201665 is an equidigital number, since it uses as much as digits as its factorization.

111215201665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22243040338.

The product of its (nonzero) digits is 3600, while the sum is 31.

Adding to 111215201665 its reverse (566102512111), we get a palindrome (677317713776).

The spelling of 111215201665 in words is "one hundred eleven billion, two hundred fifteen million, two hundred one thousand, six hundred sixty-five".