21300312221 has 2 divisors, whose sum is σ = 21300312222. Its totient is φ = 21300312220.

The previous prime is 21300312211. The next prime is 21300312233. The reversal of 21300312221 is 12221300312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17526052996 + 3774259225 = 132386^2 + 61435^2 .

It is a cyclic number.

It is not a de Polignac number, because 21300312221 - 2²² = 21296117917 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21300312221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21300312211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10650156110 + 10650156111.

It is an arithmetic number, because the mean of its divisors is an integer number (10650156111).

Almost surely, 2^21300312221 is an apocalyptic number.

It is an amenable number.

21300312221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21300312221 is an equidigital number, since it uses as much as digits as its factorization.

21300312221 is an evil number, because the sum of its binary digits is even.

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

Adding to 21300312221 its reverse (12221300312), we get a palindrome (33521612533).

The spelling of 21300312221 in words is "twenty-one billion, three hundred million, three hundred twelve thousand, two hundred twenty-one".