21002110221 has 16 divisors (see below), whose sum is σ = 29280374784. Its totient is φ = 13365128304.

The previous prime is 21002110219. The next prime is 21002110247. The reversal of 21002110221 is 12201120012.

It is not a de Polignac number, because 21002110221 - 2¹ = 21002110219 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21002110197 and 21002110206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002110321) 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 15 ways as a sum of consecutive naturals, for example, 278901 + ... + 346106.

It is an arithmetic number, because the mean of its divisors is an integer number (1830023424).

Almost surely, 2^21002110221 is an apocalyptic number.

It is an amenable number.

21002110221 is a deficient number, since it is larger than the sum of its proper divisors (8278264563).

21002110221 is a wasteful number, since it uses less digits than its factorization.

21002110221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 625520.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21002110221 its reverse (12201120012), we get a palindrome (33203230233).

The spelling of 21002110221 in words is "twenty-one billion, two million, one hundred ten thousand, two hundred twenty-one".