21584309449 has 2 divisors, whose sum is σ = 21584309450. Its totient is φ = 21584309448.

The previous prime is 21584309429. The next prime is 21584309507. The reversal of 21584309449 is 94490348512.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21570209424 + 14100025 = 146868^2 + 3755^2 .

It is a cyclic number.

It is not a de Polignac number, because 21584309449 - 2⁷ = 21584309321 is a prime.

It is not a weakly prime, because it can be changed into another prime (21584309419) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10792154724 + 10792154725.

It is an arithmetic number, because the mean of its divisors is an integer number (10792154725).

Almost surely, 2^21584309449 is an apocalyptic number.

It is an amenable number.

21584309449 is a deficient number, since it is larger than the sum of its proper divisors (1).

21584309449 is an equidigital number, since it uses as much as digits as its factorization.

21584309449 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1244160, while the sum is 49.

The spelling of 21584309449 in words is "twenty-one billion, five hundred eighty-four million, three hundred nine thousand, four hundred forty-nine".