1211115665 has 8 divisors (see below), whose sum is σ = 1470849408. Its totient is φ = 957218800.

The previous prime is 1211115641. The next prime is 1211115673. The reversal of 1211115665 is 5665111121.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1211115665 - 2¹⁶ = 1211050129 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1458761 + ... + 1459590.

It is an arithmetic number, because the mean of its divisors is an integer number (183856176).

Almost surely, 2^1211115665 is an apocalyptic number.

It is an amenable number.

1211115665 is a deficient number, since it is larger than the sum of its proper divisors (259733743).

1211115665 is an equidigital number, since it uses as much as digits as its factorization.

1211115665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2918439.

The product of its digits is 1800, while the sum is 29.

The square root of 1211115665 is about 34801.0871238242. The cubic root of 1211115665 is about 1065.9296444572.

Adding to 1211115665 its reverse (5665111121), we get a palindrome (6876226786).

The spelling of 1211115665 in words is "one billion, two hundred eleven million, one hundred fifteen thousand, six hundred sixty-five".