21020133311 has 4 divisors (see below), whose sum is σ = 21333866712. Its totient is φ = 20706399912.

The previous prime is 21020133241. The next prime is 21020133349. The reversal of 21020133311 is 11333102012.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21020133311 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21020133311.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020133611) 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, 156866600 + ... + 156866733.

It is an arithmetic number, because the mean of its divisors is an integer number (5333466678).

Almost surely, 2^21020133311 is an apocalyptic number.

21020133311 is a deficient number, since it is larger than the sum of its proper divisors (313733401).

21020133311 is an equidigital number, since it uses as much as digits as its factorization.

21020133311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 313733400.

The product of its (nonzero) digits is 108, while the sum is 17.

Adding to 21020133311 its reverse (11333102012), we get a palindrome (32353235323).

The spelling of 21020133311 in words is "twenty-one billion, twenty million, one hundred thirty-three thousand, three hundred eleven".