1278721 has 2 divisors, whose sum is σ = 1278722. Its totient is φ = 1278720.

The previous prime is 1278713. The next prime is 1278733.

1278721 is nontrivially palindromic in base 10.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 874225 + 404496 = 935^2 + 636^2 .

It is a palprime.

It is a cyclic number.

It is not a de Polignac number, because 1278721 - 2³ = 1278713 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a self number, because there is not a number n which added to its sum of digits gives 1278721.

It is not a weakly prime, because it can be changed into another prime (1278701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 639360 + 639361.

It is an arithmetic number, because the mean of its divisors is an integer number (639361).

2^1278721 is an apocalyptic number.

It is an amenable number.

1278721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1278721 is an equidigital number, since it uses as much as digits as its factorization.

1278721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1568, while the sum is 28.

The square root of 1278721 is about 1130.8054651442. The cubic root of 1278721 is about 108.5405286522.

The spelling of 1278721 in words is "one million, two hundred seventy-eight thousand, seven hundred twenty-one".