78909139 has 2 divisors, whose sum is σ = 78909140. Its totient is φ = 78909138.

The previous prime is 78909119. The next prime is 78909151. The reversal of 78909139 is 93190987.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78909139 - 2⁷ = 78909011 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (78909119) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39454569 + 39454570.

It is an arithmetic number, because the mean of its divisors is an integer number (39454570).

Almost surely, 2^78909139 is an apocalyptic number.

78909139 is a deficient number, since it is larger than the sum of its proper divisors (1).

78909139 is an equidigital number, since it uses as much as digits as its factorization.

78909139 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 122472, while the sum is 46.

The square root of 78909139 is about 8883.0816161960. The cubic root of 78909139 is about 428.9194774638.

The spelling of 78909139 in words is "seventy-eight million, nine hundred nine thousand, one hundred thirty-nine".