21011020221111 has 64 divisors (see below), whose sum is σ = 29639569697280. Its totient is φ = 13220053862400.

The previous prime is 21011020221091. The next prime is 21011020221151. The reversal of 21011020221111 is 11112202011012.

It is a happy number.

It is not a de Polignac number, because 21011020221111 - 2²¹ = 21011018123959 is a prime.

It is a super-4 number, since 4×21011020221111⁴ (a number of 54 digits) contains 4444 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011020221151) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3714160195 + ... + 3714165851.

It is an arithmetic number, because the mean of its divisors is an integer number (463118276520).

Almost surely, 2^{21011020221111} is an apocalyptic number.

21011020221111 is a deficient number, since it is larger than the sum of its proper divisors (8628549476169).

21011020221111 is a wasteful number, since it uses less digits than its factorization.

21011020221111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10544.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21011020221111 its reverse (11112202011012), we get a palindrome (32123222232123).

The spelling of 21011020221111 in words is "twenty-one trillion, eleven billion, twenty million, two hundred twenty-one thousand, one hundred eleven".