21011020211101 has 4 divisors (see below), whose sum is σ = 21028811084604. Its totient is φ = 20993229337600.

The previous prime is 21011020211099. The next prime is 21011020211113. The reversal of 21011020211101 is 10111202011012.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 8927540434201 + 12083479776900 = 2987899^2 + 3476130^2 .

It is a cyclic number.

It is not a de Polignac number, because 21011020211101 - 2¹ = 21011020211099 is a prime.

It is a super-2 number, since 2×21011020211101² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011020211131) 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, 8895434980 + ... + 8895437341.

It is an arithmetic number, because the mean of its divisors is an integer number (5257202771151).

Almost surely, 2^{21011020211101} is an apocalyptic number.

It is an amenable number.

21011020211101 is a deficient number, since it is larger than the sum of its proper divisors (17790873503).

21011020211101 is a wasteful number, since it uses less digits than its factorization.

21011020211101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17790873502.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21011020211101 its reverse (10111202011012), we get a palindrome (31122222222113).

The spelling of 21011020211101 in words is "twenty-one trillion, eleven billion, twenty million, two hundred eleven thousand, one hundred one".