1211111001000 has 512 divisors, whose sum is σ = 4276516608000. Its totient is φ = 317011968000.

The previous prime is 1211111000923. The next prime is 1211111001101. The reversal of 1211111001000 is 1001111121.

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

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 386071432 + ... + 386074568.

It is an arithmetic number, because the mean of its divisors is an integer number (8352571500).

Almost surely, 2^{1211111001000} is an apocalyptic number.

1211111001000 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 1211111001000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2138258304000).

1211111001000 is an abundant number, since it is smaller than the sum of its proper divisors (3065405607000).

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

1211111001000 is a wasteful number, since it uses less digits than its factorization.

1211111001000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3427 (or 3407 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 9.

Adding to 1211111001000 its reverse (1001111121), we get a palindrome (1212112112121).

The spelling of 1211111001000 in words is "one trillion, two hundred eleven billion, one hundred eleven million, one thousand".