78047939 has 2 divisors, whose sum is σ = 78047940. Its totient is φ = 78047938.

The previous prime is 78047933. The next prime is 78047989. The reversal of 78047939 is 93974087.

It is a weak prime.

It is an emirp because it is prime and its reverse (93974087) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78047939 - 2⁴ = 78047923 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 78047893 and 78047902.

It is not a weakly prime, because it can be changed into another prime (78047933) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39023969 + 39023970.

It is an arithmetic number, because the mean of its divisors is an integer number (39023970).

Almost surely, 2^78047939 is an apocalyptic number.

78047939 is a deficient number, since it is larger than the sum of its proper divisors (1).

78047939 is an equidigital number, since it uses as much as digits as its factorization.

78047939 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 381024, while the sum is 47.

The square root of 78047939 is about 8834.4744608833. The cubic root of 78047939 is about 427.3533831426.

The spelling of 78047939 in words is "seventy-eight million, forty-seven thousand, nine hundred thirty-nine".