78043813 has 2 divisors, whose sum is σ = 78043814. Its totient is φ = 78043812.

The previous prime is 78043751. The next prime is 78043817. The reversal of 78043813 is 31834087.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75377124 + 2666689 = 8682^2 + 1633^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78043813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78043817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39021906 + 39021907.

It is an arithmetic number, because the mean of its divisors is an integer number (39021907).

Almost surely, 2^78043813 is an apocalyptic number.

It is an amenable number.

78043813 is a deficient number, since it is larger than the sum of its proper divisors (1).

78043813 is an equidigital number, since it uses as much as digits as its factorization.

78043813 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 78043813 is about 8834.2409407940. The cubic root of 78043813 is about 427.3458523389.

The spelling of 78043813 in words is "seventy-eight million, forty-three thousand, eight hundred thirteen".