1311101661 has 4 divisors (see below), whose sum is σ = 1748135552. Its totient is φ = 874067772.

The previous prime is 1311101653. The next prime is 1311101713. The reversal of 1311101661 is 1661011131.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 1311101661 - 2³ = 1311101653 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1311101641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 218516941 + ... + 218516946.

It is an arithmetic number, because the mean of its divisors is an integer number (437033888).

Almost surely, 2^1311101661 is an apocalyptic number.

It is an amenable number.

1311101661 is a deficient number, since it is larger than the sum of its proper divisors (437033891).

1311101661 is an equidigital number, since it uses as much as digits as its factorization.

1311101661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 437033890.

The product of its (nonzero) digits is 108, while the sum is 21.

The square root of 1311101661 is about 36209.1378107792. The cubic root of 1311101661 is about 1094.4908180793.

Adding to 1311101661 its reverse (1661011131), we get a palindrome (2972112792).

The spelling of 1311101661 in words is "one billion, three hundred eleven million, one hundred one thousand, six hundred sixty-one".