1278397 has 2 divisors, whose sum is σ = 1278398. Its totient is φ = 1278396.

The previous prime is 1278391. The next prime is 1278401. The reversal of 1278397 is 7938721.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 729316 + 549081 = 854^2 + 741^2 .

It is a cyclic number.

It is not a de Polignac number, because 1278397 - 2¹⁹ = 754109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1278391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 639198 + 639199.

It is an arithmetic number, because the mean of its divisors is an integer number (639199).

2^1278397 is an apocalyptic number.

It is an amenable number.

1278397 is a deficient number, since it is larger than the sum of its proper divisors (1).

1278397 is an equidigital number, since it uses as much as digits as its factorization.

1278397 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21168, while the sum is 37.

The square root of 1278397 is about 1130.6621953528. The cubic root of 1278397 is about 108.5313606106.

It can be divided in two parts, 12783 and 97, that added together give a triangular number (12880 = T₁₆₀).

The spelling of 1278397 in words is "one million, two hundred seventy-eight thousand, three hundred ninety-seven".