21303202121 has 4 divisors (see below), whose sum is σ = 21305897472. Its totient is φ = 21300506772.

The previous prime is 21303202099. The next prime is 21303202189. The reversal of 21303202121 is 12120230312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21303202121 - 2¹⁰ = 21303201097 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21303202121.

It is not an unprimeable number, because it can be changed into a prime (21303202721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1335785 + ... + 1351638.

It is an arithmetic number, because the mean of its divisors is an integer number (5326474368).

Almost surely, 2^21303202121 is an apocalyptic number.

It is an amenable number.

21303202121 is a deficient number, since it is larger than the sum of its proper divisors (2695351).

21303202121 is an equidigital number, since it uses as much as digits as its factorization.

21303202121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2695350.

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 21303202121 its reverse (12120230312), we get a palindrome (33423432433).

The spelling of 21303202121 in words is "twenty-one billion, three hundred three million, two hundred two thousand, one hundred twenty-one".