21002101221 has 8 divisors (see below), whose sum is σ = 28003993920. Its totient is φ = 14000804672.

The previous prime is 21002101181. The next prime is 21002101249. The reversal of 21002101221 is 12210120012.

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 21002101221 - 2⁹ = 21002100709 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21002101197 and 21002101206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002100221) 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, 59076 + ... + 213293.

It is an arithmetic number, because the mean of its divisors is an integer number (3500499240).

Almost surely, 2^21002101221 is an apocalyptic number.

It is an amenable number.

21002101221 is a deficient number, since it is larger than the sum of its proper divisors (7001892699).

21002101221 is a wasteful number, since it uses less digits than its factorization.

21002101221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 298075.

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

Adding to 21002101221 its reverse (12210120012), we get a palindrome (33212221233).

The spelling of 21002101221 in words is "twenty-one billion, two million, one hundred one thousand, two hundred twenty-one".