21201100201021 has 16 divisors (see below), whose sum is σ = 22889063075760. Its totient is φ = 19521356405760.

The previous prime is 21201100201013. The next prime is 21201100201031. The reversal of 21201100201021 is 12010200110212.

It can be written as a sum of positive squares in 8 ways, for example, as 3631841136121 + 17569259064900 = 1905739^2 + 4191570^2 .

It is a cyclic number.

It is not a de Polignac number, because 21201100201021 - 2³ = 21201100201013 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21201100200992 and 21201100201010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201100201031) 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, 7132335 + ... + 9657763.

It is an arithmetic number, because the mean of its divisors is an integer number (1430566442235).

Almost surely, 2^{21201100201021} is an apocalyptic number.

It is an amenable number.

21201100201021 is a deficient number, since it is larger than the sum of its proper divisors (1687962874739).

21201100201021 is a wasteful number, since it uses less digits than its factorization.

21201100201021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2527056.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21201100201021 its reverse (12010200110212), we get a palindrome (33211300311233).

The spelling of 21201100201021 in words is "twenty-one trillion, two hundred one billion, one hundred million, two hundred one thousand, twenty-one".