11565987840 has 384 divisors, whose sum is σ = 44862854400. Its totient is φ = 2803138560.

The previous prime is 11565987821. The next prime is 11565987841. The reversal of 11565987840 is 4878956511.

It is a happy number.

11565987840 is a `hidden beast` number, since 1 + 1 + 5 + 6 + 598 + 7 + 8 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11565987841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3039379 + ... + 3043181.

It is an arithmetic number, because the mean of its divisors is an integer number (116830350).

Almost surely, 2^11565987840 is an apocalyptic number.

11565987840 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 11565987840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22431427200).

11565987840 is an abundant number, since it is smaller than the sum of its proper divisors (33296866560).

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

11565987840 is a wasteful number, since it uses less digits than its factorization.

11565987840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3850 (or 3824 counting only the distinct ones).

The product of its (nonzero) digits is 2419200, while the sum is 54.

The spelling of 11565987840 in words is "eleven billion, five hundred sixty-five million, nine hundred eighty-seven thousand, eight hundred forty".