139778831 has 2 divisors, whose sum is σ = 139778832. Its totient is φ = 139778830.

The previous prime is 139778809. The next prime is 139778851. The reversal of 139778831 is 138877931.

139778831 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is an emirp because it is prime and its reverse (138877931) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 139778831 - 2¹⁸ = 139516687 is a prime.

It is a super-2 number, since 2×139778831² = 39076243191453122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (139778851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69889415 + 69889416.

It is an arithmetic number, because the mean of its divisors is an integer number (69889416).

Almost surely, 2^139778831 is an apocalyptic number.

139778831 is a deficient number, since it is larger than the sum of its proper divisors (1).

139778831 is an equidigital number, since it uses as much as digits as its factorization.

139778831 is an evil number, because the sum of its binary digits is even.

The product of its digits is 254016, while the sum is 47.

The square root of 139778831 is about 11822.8097760219. The cubic root of 139778831 is about 518.9758330402.

The spelling of 139778831 in words is "one hundred thirty-nine million, seven hundred seventy-eight thousand, eight hundred thirty-one".