11811318640 has 80 divisors (see below), whose sum is σ = 30108787200. Its totient is φ = 4273378560.

The previous prime is 11811318637. The next prime is 11811318641. The reversal of 11811318640 is 4681311811.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×11811318640² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 11811318596 and 11811318605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11811318641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 141397 + ... + 208843.

It is an arithmetic number, because the mean of its divisors is an integer number (376359840).

Almost surely, 2^11811318640 is an apocalyptic number.

11811318640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 11811318640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15054393600).

11811318640 is an abundant number, since it is smaller than the sum of its proper divisors (18297468560).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

11811318640 is a wasteful number, since it uses less digits than its factorization.

11811318640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67670 (or 67664 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 34.

The spelling of 11811318640 in words is "eleven billion, eight hundred eleven million, three hundred eighteen thousand, six hundred forty".