11661321211 has 4 divisors (see below), whose sum is σ = 11694927672. Its totient is φ = 11627714752.

The previous prime is 11661321179. The next prime is 11661321223. The reversal of 11661321211 is 11212316611.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11212316611 = 3931 ⋅2852281.

It is a cyclic number.

It is not a de Polignac number, because 11661321211 - 2⁵ = 11661321179 is a prime.

It is a super-2 number, since 2×11661321211² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11661321911) 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, 16802710 + ... + 16803403.

It is an arithmetic number, because the mean of its divisors is an integer number (2923731918).

Almost surely, 2^11661321211 is an apocalyptic number.

11661321211 is a deficient number, since it is larger than the sum of its proper divisors (33606461).

11661321211 is an equidigital number, since it uses as much as digits as its factorization.

11661321211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33606460.

The product of its digits is 432, while the sum is 25.

Adding to 11661321211 its reverse (11212316611), we get a palindrome (22873637822).

The spelling of 11661321211 in words is "eleven billion, six hundred sixty-one million, three hundred twenty-one thousand, two hundred eleven".