210221100010021 has 16 divisors (see below), whose sum is σ = 224229480635376. Its totient is φ = 196397740071936.

The previous prime is 210221100010007. The next prime is 210221100010037. The reversal of 210221100010021 is 120010001122012.

It can be written as a sum of positive squares in 8 ways, for example, as 22157863641796 + 188063236368225 = 4707214^2 + 13713615^2 .

It is a cyclic number.

It is not a de Polignac number, because 210221100010021 - 2¹⁵ = 210221099977253 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 210221100009983 and 210221100010010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (210224100010021) 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, 36839506 + ... + 42161491.

It is an arithmetic number, because the mean of its divisors is an integer number (14014342539711).

Almost surely, 2^{210221100010021} is an apocalyptic number.

It is an amenable number.

210221100010021 is a deficient number, since it is larger than the sum of its proper divisors (14008380625355).

210221100010021 is a wasteful number, since it uses less digits than its factorization.

210221100010021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79002168.

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

Adding to 210221100010021 its reverse (120010001122012), we get a palindrome (330231101132033).

The spelling of 210221100010021 in words is "two hundred ten trillion, two hundred twenty-one billion, one hundred million, ten thousand, twenty-one".