21304439449 has 2 divisors, whose sum is σ = 21304439450. Its totient is φ = 21304439448.

The previous prime is 21304439437. The next prime is 21304439549. The reversal of 21304439449 is 94493440312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20024231049 + 1280208400 = 141507^2 + 35780^2 .

It is a cyclic number.

It is not a de Polignac number, because 21304439449 - 2⁹ = 21304438937 is a prime.

It is a super-2 number, since 2×21304439449² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21304439249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10652219724 + 10652219725.

It is an arithmetic number, because the mean of its divisors is an integer number (10652219725).

Almost surely, 2^21304439449 is an apocalyptic number.

It is an amenable number.

21304439449 is a deficient number, since it is larger than the sum of its proper divisors (1).

21304439449 is an equidigital number, since it uses as much as digits as its factorization.

21304439449 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 373248, while the sum is 43.

The spelling of 21304439449 in words is "twenty-one billion, three hundred four million, four hundred thirty-nine thousand, four hundred forty-nine".