21255449 has 2 divisors, whose sum is σ = 21255450. Its totient is φ = 21255448.

The previous prime is 21255439. The next prime is 21255467. The reversal of 21255449 is 94455212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17073424 + 4182025 = 4132^2 + 2045^2 .

It is a cyclic number.

It is not a de Polignac number, because 21255449 - 2¹² = 21251353 is a prime.

It is a super-2 number, since 2×21255449² = 903588224383202, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21255419) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10627724 + 10627725.

It is an arithmetic number, because the mean of its divisors is an integer number (10627725).

Almost surely, 2^21255449 is an apocalyptic number.

It is an amenable number.

21255449 is a deficient number, since it is larger than the sum of its proper divisors (1).

21255449 is an equidigital number, since it uses as much as digits as its factorization.

21255449 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14400, while the sum is 32.

The square root of 21255449 is about 4610.3632177953. The cubic root of 21255449 is about 277.0065857931.

The spelling of 21255449 in words is "twenty-one million, two hundred fifty-five thousand, four hundred forty-nine".