678790391 has 2 divisors, whose sum is σ = 678790392. Its totient is φ = 678790390.

The previous prime is 678790381. The next prime is 678790417. The reversal of 678790391 is 193097876.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 678790391 - 2¹⁴ = 678774007 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (678790381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 339395195 + 339395196.

It is an arithmetic number, because the mean of its divisors is an integer number (339395196).

Almost surely, 2^678790391 is an apocalyptic number.

678790391 is a deficient number, since it is larger than the sum of its proper divisors (1).

678790391 is an equidigital number, since it uses as much as digits as its factorization.

678790391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 571536, while the sum is 50.

The square root of 678790391 is about 26053.6061035704. The cubic root of 678790391 is about 878.8442088031.

The spelling of 678790391 in words is "six hundred seventy-eight million, seven hundred ninety thousand, three hundred ninety-one".