11111400781 has 4 divisors (see below), whose sum is σ = 11966123932. Its totient is φ = 10256677632.

The previous prime is 11111400749. The next prime is 11111400791. The reversal of 11111400781 is 18700411111.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 447534025 + 10663866756 = 21155^2 + 103266^2 .

It is a cyclic number.

It is not a de Polignac number, because 11111400781 - 2⁵ = 11111400749 is a prime.

It is a super-2 number, since 2×11111400781² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11111400701) 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, 427361556 + ... + 427361581.

It is an arithmetic number, because the mean of its divisors is an integer number (2991530983).

Almost surely, 2^11111400781 is an apocalyptic number.

It is an amenable number.

11111400781 is a deficient number, since it is larger than the sum of its proper divisors (854723151).

11111400781 is an equidigital number, since it uses as much as digits as its factorization.

11111400781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 854723150.

The product of its (nonzero) digits is 224, while the sum is 25.

Adding to 11111400781 its reverse (18700411111), we get a palindrome (29811811892).

The spelling of 11111400781 in words is "eleven billion, one hundred eleven million, four hundred thousand, seven hundred eighty-one".