21311211203311 has 4 divisors (see below), whose sum is σ = 21316420498824. Its totient is φ = 21306001907800.

The previous prime is 21311211203299. The next prime is 21311211203363. The reversal of 21311211203311 is 11330211211312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21311211203311 - 2⁴¹ = 19112187947759 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311241203311) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2604641620 + ... + 2604649801.

It is an arithmetic number, because the mean of its divisors is an integer number (5329105124706).

Almost surely, 2^{21311211203311} is an apocalyptic number.

21311211203311 is a deficient number, since it is larger than the sum of its proper divisors (5209295513).

21311211203311 is an equidigital number, since it uses as much as digits as its factorization.

21311211203311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5209295512.

The product of its (nonzero) digits is 216, while the sum is 22.

Adding to 21311211203311 its reverse (11330211211312), we get a palindrome (32641422414623).

The spelling of 21311211203311 in words is "twenty-one trillion, three hundred eleven billion, two hundred eleven million, two hundred three thousand, three hundred eleven".