78815543 has 2 divisors, whose sum is σ = 78815544. Its totient is φ = 78815542.

The previous prime is 78815501. The next prime is 78815557. The reversal of 78815543 is 34551887.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78815543 - 2⁶ = 78815479 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 78815543.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78875543) 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, 39407771 + 39407772.

It is an arithmetic number, because the mean of its divisors is an integer number (39407772).

Almost surely, 2^78815543 is an apocalyptic number.

78815543 is a deficient number, since it is larger than the sum of its proper divisors (1).

78815543 is an equidigital number, since it uses as much as digits as its factorization.

78815543 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 134400, while the sum is 41.

The square root of 78815543 is about 8877.8118362579. The cubic root of 78815543 is about 428.7498265178.

The spelling of 78815543 in words is "seventy-eight million, eight hundred fifteen thousand, five hundred forty-three".