139678391 has 2 divisors, whose sum is σ = 139678392. Its totient is φ = 139678390.

The previous prime is 139678381. The next prime is 139678417. The reversal of 139678391 is 193876931.

It is a happy number.

139678391 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 139678391 - 2¹⁴ = 139662007 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 (139678361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69839195 + 69839196.

It is an arithmetic number, because the mean of its divisors is an integer number (69839196).

Almost surely, 2^139678391 is an apocalyptic number.

139678391 is a deficient number, since it is larger than the sum of its proper divisors (1).

139678391 is an equidigital number, since it uses as much as digits as its factorization.

139678391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 244944, while the sum is 47.

The square root of 139678391 is about 11818.5612914601. The cubic root of 139678391 is about 518.8514975154.

The spelling of 139678391 in words is "one hundred thirty-nine million, six hundred seventy-eight thousand, three hundred ninety-one".