21149449 has 2 divisors, whose sum is σ = 21149450. Its totient is φ = 21149448.

The previous prime is 21149417. The next prime is 21149461. The reversal of 21149449 is 94494112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12924025 + 8225424 = 3595^2 + 2868^2 .

It is a cyclic number.

It is not a de Polignac number, because 21149449 - 2⁵ = 21149417 is a prime.

It is not a weakly prime, because it can be changed into another prime (21149549) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10574724 + 10574725.

It is an arithmetic number, because the mean of its divisors is an integer number (10574725).

Almost surely, 2^21149449 is an apocalyptic number.

It is an amenable number.

21149449 is a deficient number, since it is larger than the sum of its proper divisors (1).

21149449 is an equidigital number, since it uses as much as digits as its factorization.

21149449 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10368, while the sum is 34.

The square root of 21149449 is about 4598.8530091752. The cubic root of 21149449 is about 276.5453449455.

The spelling of 21149449 in words is "twenty-one million, one hundred forty-nine thousand, four hundred forty-nine".