1278139 has 2 divisors, whose sum is σ = 1278140. Its totient is φ = 1278138.

The previous prime is 1278131. The next prime is 1278163. The reversal of 1278139 is 9318721.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1278139 - 2³ = 1278131 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1278139.

It is not a weakly prime, because it can be changed into another prime (1278131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 639069 + 639070.

It is an arithmetic number, because the mean of its divisors is an integer number (639070).

2^1278139 is an apocalyptic number.

1278139 is a deficient number, since it is larger than the sum of its proper divisors (1).

1278139 is an equidigital number, since it uses as much as digits as its factorization.

1278139 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 31.

The square root of 1278139 is about 1130.5480971635. The cubic root of 1278139 is about 108.5240590251.

The spelling of 1278139 in words is "one million, two hundred seventy-eight thousand, one hundred thirty-nine".