21211111020101 has 4 divisors (see below), whose sum is σ = 21211130933292. Its totient is φ = 21211091106912.

The previous prime is 21211111020091. The next prime is 21211111020103. The reversal of 21211111020101 is 10102011111212.

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 13701324340900 + 7509786679201 = 3701530^2 + 2740399^2 .

It is a cyclic number.

It is not a de Polignac number, because 21211111020101 - 2¹⁸ = 21211110757957 is a prime.

It is a super-2 number, since 2×21211111020101² (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 (21211111020103) 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, 8262776 + ... + 10521201.

It is an arithmetic number, because the mean of its divisors is an integer number (5302782733323).

Almost surely, 2^{21211111020101} is an apocalyptic number.

It is an amenable number.

21211111020101 is a deficient number, since it is larger than the sum of its proper divisors (19913191).

21211111020101 is a wasteful number, since it uses less digits than its factorization.

21211111020101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19913190.

The product of its (nonzero) digits is 8, while the sum is 14.

Adding to 21211111020101 its reverse (10102011111212), we get a palindrome (31313122131313).

The spelling of 21211111020101 in words is "twenty-one trillion, two hundred eleven billion, one hundred eleven million, twenty thousand, one hundred one".