11111111001000 has 384 divisors, whose sum is σ = 37930891714560. Its totient is φ = 2933449344000.

The previous prime is 11111111000933. The next prime is 11111111001031. The reversal of 11111111001000 is 10011111111.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 556631020 + ... + 556650980.

It is an arithmetic number, because the mean of its divisors is an integer number (98778363840).

Almost surely, 2^{11111111001000} is an apocalyptic number.

11111111001000 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 11111111001000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18965445857280).

11111111001000 is an abundant number, since it is smaller than the sum of its proper divisors (26819780713560).

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

11111111001000 is a wasteful number, since it uses less digits than its factorization.

11111111001000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20602 (or 20585 counting only the distinct ones).

The product of its (nonzero) digits is 1, while the sum is 9.

Adding to 11111111001000 its reverse (10011111111), we get a palindrome (11121122112111).

The spelling of 11111111001000 in words is "eleven trillion, one hundred eleven billion, one hundred eleven million, one thousand".