21011020011011 has 4 divisors (see below), whose sum is σ = 21578885416752. Its totient is φ = 20443154605272.

The previous prime is 21011020010957. The next prime is 21011020011049. The reversal of 21011020011011 is 11011002011012.

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-21011020011011 is a prime.

It is a super-2 number, since 2×21011020011011² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21011020010983 and 21011020011001.

It is not an unprimeable number, because it can be changed into a prime (21011020011911) 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, 283932702815 + ... + 283932702888.

It is an arithmetic number, because the mean of its divisors is an integer number (5394721354188).

Almost surely, 2^{21011020011011} is an apocalyptic number.

21011020011011 is a deficient number, since it is larger than the sum of its proper divisors (567865405741).

21011020011011 is an equidigital number, since it uses as much as digits as its factorization.

21011020011011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 567865405740.

The product of its (nonzero) digits is 4, while the sum is 11.

Adding to 21011020011011 its reverse (11011002011012), we get a palindrome (32022022022023).

The spelling of 21011020011011 in words is "twenty-one trillion, eleven billion, twenty million, eleven thousand, eleven".