21001120101811 has 2 divisors, whose sum is σ = 21001120101812. Its totient is φ = 21001120101810.

The previous prime is 21001120101781. The next prime is 21001120101821. The reversal of 21001120101811 is 11810102110012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21001120101811 - 2¹¹ = 21001120099763 is a prime.

It is not a weakly prime, because it can be changed into another prime (21001120101821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500560050905 + 10500560050906.

It is an arithmetic number, because the mean of its divisors is an integer number (10500560050906).

Almost surely, 2^{21001120101811} is an apocalyptic number.

21001120101811 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001120101811 is an equidigital number, since it uses as much as digits as its factorization.

21001120101811 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 19.

Adding to 21001120101811 its reverse (11810102110012), we get a palindrome (32811222211823).

The spelling of 21001120101811 in words is "twenty-one trillion, one billion, one hundred twenty million, one hundred one thousand, eight hundred eleven".