78539449 has 2 divisors, whose sum is σ = 78539450. Its totient is φ = 78539448.

The previous prime is 78539441. The next prime is 78539471. The reversal of 78539449 is 94493587.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 39601849 + 38937600 = 6293^2 + 6240^2 .

It is an emirp because it is prime and its reverse (94493587) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78539449 - 2³ = 78539441 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (78539441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39269724 + 39269725.

It is an arithmetic number, because the mean of its divisors is an integer number (39269725).

Almost surely, 2^78539449 is an apocalyptic number.

It is an amenable number.

78539449 is a deficient number, since it is larger than the sum of its proper divisors (1).

78539449 is an equidigital number, since it uses as much as digits as its factorization.

78539449 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1088640, while the sum is 49.

The square root of 78539449 is about 8862.2485295776. The cubic root of 78539449 is about 428.2485981892.

The spelling of 78539449 in words is "seventy-eight million, five hundred thirty-nine thousand, four hundred forty-nine".