78785813 has 2 divisors, whose sum is σ = 78785814. Its totient is φ = 78785812.

The previous prime is 78785807. The next prime is 78785821. The reversal of 78785813 is 31858787.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 59089969 + 19695844 = 7687^2 + 4438^2 .

It is an emirp because it is prime and its reverse (31858787) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78785813 - 2⁴ = 78785797 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78785843) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39392906 + 39392907.

It is an arithmetic number, because the mean of its divisors is an integer number (39392907).

Almost surely, 2^78785813 is an apocalyptic number.

It is an amenable number.

78785813 is a deficient number, since it is larger than the sum of its proper divisors (1).

78785813 is an equidigital number, since it uses as much as digits as its factorization.

78785813 is an evil number, because the sum of its binary digits is even.

The product of its digits is 376320, while the sum is 47.

The square root of 78785813 is about 8876.1372792448. The cubic root of 78785813 is about 428.6959101838.

The spelling of 78785813 in words is "seventy-eight million, seven hundred eighty-five thousand, eight hundred thirteen".