11689440781 has 4 divisors (see below), whose sum is σ = 11854080864. Its totient is φ = 11524800700.

The previous prime is 11689440757. The next prime is 11689440787. The reversal of 11689440781 is 18704498611.

It is a happy number.

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 a cyclic number.

It is not a de Polignac number, because 11689440781 - 2¹³ = 11689432589 is a prime.

It is a super-2 number, since 2×11689440781² (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 (11689440787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 82319935 + ... + 82320076.

It is an arithmetic number, because the mean of its divisors is an integer number (2963520216).

Almost surely, 2^11689440781 is an apocalyptic number.

It is an amenable number.

11689440781 is a deficient number, since it is larger than the sum of its proper divisors (164640083).

11689440781 is an equidigital number, since it uses as much as digits as its factorization.

11689440781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164640082.

The product of its (nonzero) digits is 387072, while the sum is 49.

The spelling of 11689440781 in words is "eleven billion, six hundred eighty-nine million, four hundred forty thousand, seven hundred eighty-one".