78440671 has 2 divisors, whose sum is σ = 78440672. Its totient is φ = 78440670.

The previous prime is 78440657. The next prime is 78440701. The reversal of 78440671 is 17604487.

It is a weak prime.

It is an emirp because it is prime and its reverse (17604487) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78440671 - 2¹⁹ = 77916383 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 78440671.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78440611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39220335 + 39220336.

It is an arithmetic number, because the mean of its divisors is an integer number (39220336).

Almost surely, 2^78440671 is an apocalyptic number.

78440671 is a deficient number, since it is larger than the sum of its proper divisors (1).

78440671 is an equidigital number, since it uses as much as digits as its factorization.

78440671 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 37632, while the sum is 37.

The square root of 78440671 is about 8856.6738113131. The cubic root of 78440671 is about 428.0689887191.

The spelling of 78440671 in words is "seventy-eight million, four hundred forty thousand, six hundred seventy-one".