1287739 has 2 divisors, whose sum is σ = 1287740. Its totient is φ = 1287738.

The previous prime is 1287731. The next prime is 1287743. The reversal of 1287739 is 9377821.

It is a strong prime.

It is an emirp because it is prime and its reverse (9377821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1287739 - 2³ = 1287731 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1287698 and 1287707.

It is not a weakly prime, because it can be changed into another prime (1287731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 643869 + 643870.

It is an arithmetic number, because the mean of its divisors is an integer number (643870).

2^1287739 is an apocalyptic number.

1287739 is a deficient number, since it is larger than the sum of its proper divisors (1).

1287739 is an equidigital number, since it uses as much as digits as its factorization.

1287739 is an evil number, because the sum of its binary digits is even.

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

The square root of 1287739 is about 1134.7858828872. The cubic root of 1287739 is about 108.7950867789.

The spelling of 1287739 in words is "one million, two hundred eighty-seven thousand, seven hundred thirty-nine".