1281649 has 2 divisors, whose sum is σ = 1281650. Its totient is φ = 1281648.

The previous prime is 1281587. The next prime is 1281653. The reversal of 1281649 is 9461821.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1281424 + 225 = 1132^2 + 15^2 .

It is an emirp because it is prime and its reverse (9461821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1281649 - 2⁷ = 1281521 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1281649.

It is not a weakly prime, because it can be changed into another prime (1281149) by changing a digit.

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

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 640824 + 640825.

It is an arithmetic number, because the mean of its divisors is an integer number (640825).

2^1281649 is an apocalyptic number.

It is an amenable number.

1281649 is a deficient number, since it is larger than the sum of its proper divisors (1).

1281649 is an equidigital number, since it uses as much as digits as its factorization.

1281649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3456, while the sum is 31.

The square root of 1281649 is about 1132.0993772633. The cubic root of 1281649 is about 108.6233104333.

It can be divided in two parts, 128164 and 9, that multiplied together give a square (1153476 = 1074²).

The spelling of 1281649 in words is "one million, two hundred eighty-one thousand, six hundred forty-nine".