21480857449 has 2 divisors, whose sum is σ = 21480857450. Its totient is φ = 21480857448.

The previous prime is 21480857371. The next prime is 21480857507. The reversal of 21480857449 is 94475808412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18829328400 + 2651529049 = 137220^2 + 51493^2 .

It is a cyclic number.

It is not a de Polignac number, because 21480857449 - 2³³ = 12890922857 is a prime.

It is a super-2 number, since 2×21480857449² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21480857396 and 21480857405.

It is not a weakly prime, because it can be changed into another prime (21480857149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10740428724 + 10740428725.

It is an arithmetic number, because the mean of its divisors is an integer number (10740428725).

Almost surely, 2^21480857449 is an apocalyptic number.

It is an amenable number.

21480857449 is a deficient number, since it is larger than the sum of its proper divisors (1).

21480857449 is an equidigital number, since it uses as much as digits as its factorization.

21480857449 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2580480, while the sum is 52.

The spelling of 21480857449 in words is "twenty-one billion, four hundred eighty million, eight hundred fifty-seven thousand, four hundred forty-nine".