210221110021 has 4 divisors (see below), whose sum is σ = 226391964652. Its totient is φ = 194050255392.

The previous prime is 210221110019. The next prime is 210221110039. The reversal of 210221110021 is 120011122012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 85562685121 + 124658424900 = 292511^2 + 353070^2 .

It is a cyclic number.

It is not a de Polignac number, because 210221110021 - 2¹ = 210221110019 is a prime.

It is a super-2 number, since 2×210221110021² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (13), and also a Moran number because the ratio is a prime number: 16170854617 = 210221110021 / (2 + 1 + 0 + 2 + 2 + 1 + 1 + 1 + 0 + 0 + 2 + 1).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 210221109983 and 210221110010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (210221110091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8085427296 + ... + 8085427321.

It is an arithmetic number, because the mean of its divisors is an integer number (56597991163).

Almost surely, 2^210221110021 is an apocalyptic number.

It is an amenable number.

210221110021 is a deficient number, since it is larger than the sum of its proper divisors (16170854631).

210221110021 is a wasteful number, since it uses less digits than its factorization.

210221110021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16170854630.

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

Adding to 210221110021 its reverse (120011122012), we get a palindrome (330232232033).

The spelling of 210221110021 in words is "two hundred ten billion, two hundred twenty-one million, one hundred ten thousand, twenty-one".