1681397 has 2 divisors, whose sum is σ = 1681398. Its totient is φ = 1681396.

The previous prime is 1681363. The next prime is 1681403. The reversal of 1681397 is 7931861.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1552516 + 128881 = 1246^2 + 359^2 .

It is a cyclic number.

It is not a de Polignac number, because 1681397 - 2¹⁰ = 1680373 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 (1681307) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 840698 + 840699.

It is an arithmetic number, because the mean of its divisors is an integer number (840699).

2^1681397 is an apocalyptic number.

It is an amenable number.

1681397 is a deficient number, since it is larger than the sum of its proper divisors (1).

1681397 is an equidigital number, since it uses as much as digits as its factorization.

1681397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9072, while the sum is 35.

The square root of 1681397 is about 1296.6869321467. The cubic root of 1681397 is about 118.9113809537.

The spelling of 1681397 in words is "one million, six hundred eighty-one thousand, three hundred ninety-seven".