1211021100000 has 864 divisors, whose sum is σ = 4533796193472. Its totient is φ = 306201600000.

The previous prime is 1211021099983. The next prime is 1211021100007. The reversal of 1211021100000 is 11201121.

It is a happy number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211021100007) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 1365299557 + ... + 1365300443.

It is an arithmetic number, because the mean of its divisors is an integer number (5247449298).

Almost surely, 2^{1211021100000} is an apocalyptic number.

1211021100000 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 1211021100000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2266898096736).

1211021100000 is an abundant number, since it is smaller than the sum of its proper divisors (3322775093472).

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

1211021100000 is an equidigital number, since it uses as much as digits as its factorization.

1211021100000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1006 (or 975 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 1211021100000 its reverse (11201121), we get a palindrome (1211032301121).

The spelling of 1211021100000 in words is "one trillion, two hundred eleven billion, twenty-one million, one hundred thousand".