21011011201021 has 16 divisors (see below), whose sum is σ = 21135282387120. Its totient is φ = 20886925086720.

The previous prime is 21011011200961. The next prime is 21011011201043. The reversal of 21011011201021 is 12010211011012.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 10299856816921 + 10711154384100 = 3209339^2 + 3272790^2 .

It is a cyclic number.

It is not a de Polignac number, because 21011011201021 - 2⁴¹ = 18811987945469 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21011011200992 and 21011011201010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011011271021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1917582475 + ... + 1917593431.

It is an arithmetic number, because the mean of its divisors is an integer number (1320955149195).

Almost surely, 2^{21011011201021} is an apocalyptic number.

It is an amenable number.

21011011201021 is a deficient number, since it is larger than the sum of its proper divisors (124271186099).

21011011201021 is a wasteful number, since it uses less digits than its factorization.

21011011201021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18384.

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

Adding to 21011011201021 its reverse (12010211011012), we get a palindrome (33021222212033).

The spelling of 21011011201021 in words is "twenty-one trillion, eleven billion, eleven million, two hundred one thousand, twenty-one".