1278401 has 2 divisors, whose sum is σ = 1278402. Its totient is φ = 1278400.

The previous prime is 1278397. The next prime is 1278419. The reversal of 1278401 is 1048721.

1278401 = 799² + 800².

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 640000 + 638401 = 800^2 + 799^2 .

It is an emirp because it is prime and its reverse (1048721) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1278401 - 2² = 1278397 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1278481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 639200 + 639201.

It is an arithmetic number, because the mean of its divisors is an integer number (639201).

2^1278401 is an apocalyptic number.

1278401 is the 800-th centered square number.

It is an amenable number.

1278401 is a deficient number, since it is larger than the sum of its proper divisors (1).

1278401 is an equidigital number, since it uses as much as digits as its factorization.

1278401 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 448, while the sum is 23.

The square root of 1278401 is about 1130.6639642263. The cubic root of 1278401 is about 108.5314738057.

The spelling of 1278401 in words is "one million, two hundred seventy-eight thousand, four hundred one".