78724643 has 2 divisors, whose sum is σ = 78724644. Its totient is φ = 78724642.

The previous prime is 78724627. The next prime is 78724669. The reversal of 78724643 is 34642787.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 78724643 - 2⁴ = 78724627 is a prime.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 78724643.

It is not a weakly prime, because it can be changed into another prime (78724693) 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, 39362321 + 39362322.

It is an arithmetic number, because the mean of its divisors is an integer number (39362322).

Almost surely, 2^78724643 is an apocalyptic number.

78724643 is a deficient number, since it is larger than the sum of its proper divisors (1).

78724643 is an equidigital number, since it uses as much as digits as its factorization.

78724643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 225792, while the sum is 41.

The square root of 78724643 is about 8872.6908545266. The cubic root of 78724643 is about 428.5849336961.

The spelling of 78724643 in words is "seventy-eight million, seven hundred twenty-four thousand, six hundred forty-three".