1211111221000 has 128 divisors (see below), whose sum is σ = 2854164418560. Its totient is φ = 481004256000.

The previous prime is 1211111220973. The next prime is 1211111221009. The reversal of 1211111221000 is 1221111121.

It is a happy number.

It is a super-2 number, since 2×1211111221000² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1211111221009) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 170503449 + ... + 170510551.

It is an arithmetic number, because the mean of its divisors is an integer number (22298159520).

Almost surely, 2^{1211111221000} is an apocalyptic number.

1211111221000 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 1211111221000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1427082209280).

1211111221000 is an abundant number, since it is smaller than the sum of its proper divisors (1643053197560).

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

1211111221000 is a wasteful number, since it uses less digits than its factorization.

1211111221000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8312 (or 8298 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 1211111221000 its reverse (1221111121), we get a palindrome (1212332332121).

The spelling of 1211111221000 in words is "one trillion, two hundred eleven billion, one hundred eleven million, two hundred twenty-one thousand".