1981297 has 2 divisors, whose sum is σ = 1981298. Its totient is φ = 1981296.

The previous prime is 1981277. The next prime is 1981337. The reversal of 1981297 is 7921891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1962801 + 18496 = 1401^2 + 136^2 .

It is an emirp because it is prime and its reverse (7921891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1981297 - 2⁷ = 1981169 is a prime.

It is a super-3 number, since 3×1981297³ = 23332968812709855219, which contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (1981237) 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, 990648 + 990649.

It is an arithmetic number, because the mean of its divisors is an integer number (990649).

2^1981297 is an apocalyptic number.

It is an amenable number.

1981297 is a deficient number, since it is larger than the sum of its proper divisors (1).

1981297 is an equidigital number, since it uses as much as digits as its factorization.

1981297 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9072, while the sum is 37.

The square root of 1981297 is about 1407.5855213805. The cubic root of 1981297 is about 125.5981359684.

It can be divided in two parts, 1981 and 297, that added together give a triangular number (2278 = T₆₇).

The spelling of 1981297 in words is "one million, nine hundred eighty-one thousand, two hundred ninety-seven".