21102002221 has 8 divisors (see below), whose sum is σ = 22362089400. Its totient is φ = 19877410560.

The previous prime is 21102002213. The next prime is 21102002227. The reversal of 21102002221 is 12220020112.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 547045321 + 20554956900 = 23389^2 + 143370^2 .

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 21102002221 - 2³ = 21102002213 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 (21102002227) 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, 8872656 + ... + 8875033.

It is an arithmetic number, because the mean of its divisors is an integer number (2795261175).

Almost surely, 2^21102002221 is an apocalyptic number.

It is an amenable number.

21102002221 is a deficient number, since it is larger than the sum of its proper divisors (1260087179).

21102002221 is a wasteful number, since it uses less digits than its factorization.

21102002221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17747759.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21102002221 its reverse (12220020112), we get a palindrome (33322022333).

The spelling of 21102002221 in words is "twenty-one billion, one hundred two million, two thousand, two hundred twenty-one".