1211111000000 has 392 divisors, whose sum is σ = 3420383718528. Its totient is φ = 421168000000.

The previous prime is 1211110999991. The next prime is 1211111000041. The reversal of 1211111000000 is 1111121.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (8).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 252997607 + ... + 253002393.

Almost surely, 2^{1211111000000} is an apocalyptic number.

1211111000000 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 1211111000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1710191859264).

1211111000000 is an abundant number, since it is smaller than the sum of its proper divisors (2209272718528).

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

1211111000000 is an frugal number, since it uses more digits than its factorization.

1211111000000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4863 (or 4828 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 8.

Adding to 1211111000000 its reverse (1111121), we get a palindrome (1211112111121).

The spelling of 1211111000000 in words is "one trillion, two hundred eleven billion, one hundred eleven million", and thus it is an aban number.