1297781 has 2 divisors, whose sum is σ = 1297782. Its totient is φ = 1297780.

The previous prime is 1297771. The next prime is 1297799. The reversal of 1297781 is 1877921.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1144900 + 152881 = 1070^2 + 391^2 .

It is a cyclic number.

It is not a de Polignac number, because 1297781 - 2¹⁸ = 1035637 is a prime.

It is a super-2 number, since 2×1297781² = 3368471047922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1297771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 648890 + 648891.

It is an arithmetic number, because the mean of its divisors is an integer number (648891).

2^1297781 is an apocalyptic number.

It is an amenable number.

1297781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1297781 is an equidigital number, since it uses as much as digits as its factorization.

1297781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7056, while the sum is 35.

The square root of 1297781 is about 1139.2019136220. The cubic root of 1297781 is about 109.0771554841.

The spelling of 1297781 in words is "one million, two hundred ninety-seven thousand, seven hundred eighty-one".