21321220313 has 2 divisors, whose sum is σ = 21321220314. Its totient is φ = 21321220312.

The previous prime is 21321220309. The next prime is 21321220337. The reversal of 21321220313 is 31302212312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20690808649 + 630411664 = 143843^2 + 25108^2 .

It is a cyclic number.

It is not a de Polignac number, because 21321220313 - 2² = 21321220309 is a prime.

It is not a weakly prime, because it can be changed into another prime (21321222313) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10660610156 + 10660610157.

It is an arithmetic number, because the mean of its divisors is an integer number (10660610157).

Almost surely, 2^21321220313 is an apocalyptic number.

It is an amenable number.

21321220313 is a deficient number, since it is larger than the sum of its proper divisors (1).

21321220313 is an equidigital number, since it uses as much as digits as its factorization.

21321220313 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 21321220313 its reverse (31302212312), we get a palindrome (52623432625).

The spelling of 21321220313 in words is "twenty-one billion, three hundred twenty-one million, two hundred twenty thousand, three hundred thirteen".