78339949 has 2 divisors, whose sum is σ = 78339950. Its totient is φ = 78339948.

The previous prime is 78339931. The next prime is 78339977. The reversal of 78339949 is 94993387.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 75811849 + 2528100 = 8707^2 + 1590^2 .

It is an emirp because it is prime and its reverse (94993387) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78339949 - 2⁵ = 78339917 is a prime.

It is a super-2 number, since 2×78339949² = 12274295218645202, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 78339896 and 78339905.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78339979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39169974 + 39169975.

It is an arithmetic number, because the mean of its divisors is an integer number (39169975).

Almost surely, 2^78339949 is an apocalyptic number.

It is an amenable number.

78339949 is a deficient number, since it is larger than the sum of its proper divisors (1).

78339949 is an equidigital number, since it uses as much as digits as its factorization.

78339949 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1469664, while the sum is 52.

The square root of 78339949 is about 8850.9857643090. The cubic root of 78339949 is about 427.8856891131.

The spelling of 78339949 in words is "seventy-eight million, three hundred thirty-nine thousand, nine hundred forty-nine".