21001020110221 has 8 divisors (see below), whose sum is σ = 22135102525080. Its totient is φ = 19894264982592.

The previous prime is 21001020110179. The next prime is 21001020110243. The reversal of 21001020110221 is 12201102010012.

It can be written as a sum of positive squares in 4 ways, for example, as 861694475625 + 20139325634596 = 928275^2 + 4487686^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21001020110221 - 2⁹ = 21001020109709 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001020110621) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6831820230 + ... + 6831823303.

It is an arithmetic number, because the mean of its divisors is an integer number (2766887815635).

Almost surely, 2^{21001020110221} is an apocalyptic number.

It is an amenable number.

21001020110221 is a deficient number, since it is larger than the sum of its proper divisors (1134082414859).

21001020110221 is a wasteful number, since it uses less digits than its factorization.

21001020110221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13663643615.

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

Adding to 21001020110221 its reverse (12201102010012), we get a palindrome (33202122120233).

The spelling of 21001020110221 in words is "twenty-one trillion, one billion, twenty million, one hundred ten thousand, two hundred twenty-one".