1211021100091 has 16 divisors (see below), whose sum is σ = 1366752261600. Its totient is φ = 1062900921600.

The previous prime is 1211021100067. The next prime is 1211021100109. The reversal of 1211021100091 is 1900011201121.

It is a cyclic number.

It is not a de Polignac number, because 1211021100091 - 2²¹ = 1211019002939 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1211021100391) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 5613481 + ... + 5825221.

It is an arithmetic number, because the mean of its divisors is an integer number (85422016350).

Almost surely, 2^{1211021100091} is an apocalyptic number.

1211021100091 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1211021100091 is a deficient number, since it is larger than the sum of its proper divisors (155731161509).

1211021100091 is a wasteful number, since it uses less digits than its factorization.

1211021100091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229710.

The product of its (nonzero) digits is 36, while the sum is 19.

The spelling of 1211021100091 in words is "one trillion, two hundred eleven billion, twenty-one million, one hundred thousand, ninety-one".