1281389 has 2 divisors, whose sum is σ = 1281390. Its totient is φ = 1281388.

The previous prime is 1281383. The next prime is 1281407. The reversal of 1281389 is 9831821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1276900 + 4489 = 1130^2 + 67^2 .

It is a cyclic number.

It is not a de Polignac number, because 1281389 - 2¹⁶ = 1215853 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1281383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 640694 + 640695.

It is an arithmetic number, because the mean of its divisors is an integer number (640695).

2^1281389 is an apocalyptic number.

It is an amenable number.

1281389 is a deficient number, since it is larger than the sum of its proper divisors (1).

1281389 is an equidigital number, since it uses as much as digits as its factorization.

1281389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3456, while the sum is 32.

The square root of 1281389 is about 1131.9845405305. The cubic root of 1281389 is about 108.6159646960.

The spelling of 1281389 in words is "one million, two hundred eighty-one thousand, three hundred eighty-nine".