21201011101021 has 16 divisors (see below), whose sum is σ = 21708685877760. Its totient is φ = 20700777875760.

The previous prime is 21201011100991. The next prime is 21201011101031. The reversal of 21201011101021 is 12010111010212.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21201011101021 - 2⁵ = 21201011100989 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21201011100992 and 21201011101010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201011101031) 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, 1955625 + ... + 6799006.

It is an arithmetic number, because the mean of its divisors is an integer number (1356792867360).

Almost surely, 2^{21201011101021} is an apocalyptic number.

It is an amenable number.

21201011101021 is a deficient number, since it is larger than the sum of its proper divisors (507674776739).

21201011101021 is a wasteful number, since it uses less digits than its factorization.

21201011101021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8755056.

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

Adding to 21201011101021 its reverse (12010111010212), we get a palindrome (33211122111233).

It can be divided in two parts, 2 and 1201011101021, that multiplied together give a palindrome (2402022202042).

The spelling of 21201011101021 in words is "twenty-one trillion, two hundred one billion, eleven million, one hundred one thousand, twenty-one".