78391387 has 2 divisors, whose sum is σ = 78391388. Its totient is φ = 78391386.

The previous prime is 78391381. The next prime is 78391393. The reversal of 78391387 is 78319387.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (78391381) and next prime (78391393).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78391387 is a prime.

It is a super-2 number, since 2×78391387² = 12290419111567538, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78391381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39195693 + 39195694.

It is an arithmetic number, because the mean of its divisors is an integer number (39195694).

Almost surely, 2^78391387 is an apocalyptic number.

78391387 is a deficient number, since it is larger than the sum of its proper divisors (1).

78391387 is an equidigital number, since it uses as much as digits as its factorization.

78391387 is an evil number, because the sum of its binary digits is even.

The product of its digits is 254016, while the sum is 46.

The square root of 78391387 is about 8853.8910655146. The cubic root of 78391387 is about 427.9793185191.

The spelling of 78391387 in words is "seventy-eight million, three hundred ninety-one thousand, three hundred eighty-seven".