1211001020100 has 432 divisors, whose sum is σ = 3936681036288. Its totient is φ = 311139118080.

The previous prime is 1211001020083. The next prime is 1211001020129. The reversal of 1211001020100 is 10201001121.

It is a happy number.

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 143 ways as a sum of consecutive naturals, for example, 2407556449 + ... + 2407556951.

It is an arithmetic number, because the mean of its divisors is an integer number (9112687584).

Almost surely, 2^{1211001020100} is an apocalyptic number.

1211001020100 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 1211001020100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1968340518144).

1211001020100 is an abundant number, since it is smaller than the sum of its proper divisors (2725680016188).

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

1211001020100 is a wasteful number, since it uses less digits than its factorization.

1211001020100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1124 (or 1114 counting only the distinct ones).

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

Adding to 1211001020100 its reverse (10201001121), we get a palindrome (1221202021221).

The spelling of 1211001020100 in words is "one trillion, two hundred eleven billion, one million, twenty thousand, one hundred".