21002221021 has 8 divisors (see below), whose sum is σ = 21285200000. Its totient is φ = 20719670400.

The previous prime is 21002220997. The next prime is 21002221027. The reversal of 21002221021 is 12012220012.

It is a happy number.

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 21002221021 - 2³³ = 12412286429 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21002220992 and 21002221010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002221027) 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, 7755 + ... + 205096.

It is an arithmetic number, because the mean of its divisors is an integer number (2660650000).

Almost surely, 2^21002221021 is an apocalyptic number.

It is an amenable number.

21002221021 is a deficient number, since it is larger than the sum of its proper divisors (282978979).

21002221021 is a wasteful number, since it uses less digits than its factorization.

21002221021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214179.

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

Adding to 21002221021 its reverse (12012220012), we get a palindrome (33014441033).

The spelling of 21002221021 in words is "twenty-one billion, two million, two hundred twenty-one thousand, twenty-one".