1311217161 has 4 divisors (see below), whose sum is σ = 1748289552. Its totient is φ = 874144772.

The previous prime is 1311217109. The next prime is 1311217231. The reversal of 1311217161 is 1617121131.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1617121131 = 3 ⋅539040377.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1311217161 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1311215161) 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, 218536191 + ... + 218536196.

It is an arithmetic number, because the mean of its divisors is an integer number (437072388).

Almost surely, 2^1311217161 is an apocalyptic number.

It is an amenable number.

1311217161 is a deficient number, since it is larger than the sum of its proper divisors (437072391).

1311217161 is an equidigital number, since it uses as much as digits as its factorization.

1311217161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 437072390.

The product of its digits is 252, while the sum is 24.

The square root of 1311217161 is about 36210.7326769288. The cubic root of 1311217161 is about 1094.5229564408.

Adding to 1311217161 its reverse (1617121131), we get a palindrome (2928338292).

The spelling of 1311217161 in words is "one billion, three hundred eleven million, two hundred seventeen thousand, one hundred sixty-one".