1391281 has 2 divisors, whose sum is σ = 1391282. Its totient is φ = 1391280.

The previous prime is 1391267. The next prime is 1391287. The reversal of 1391281 is 1821931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1175056 + 216225 = 1084^2 + 465^2 .

It is a cyclic number.

It is not a de Polignac number, because 1391281 - 2¹¹ = 1389233 is a prime.

It is a super-2 number, since 2×1391281² = 3871325641922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1391287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 695640 + 695641.

It is an arithmetic number, because the mean of its divisors is an integer number (695641).

2^1391281 is an apocalyptic number.

1391281 is the 528-th centered decagonal number.

It is an amenable number.

1391281 is a deficient number, since it is larger than the sum of its proper divisors (1).

1391281 is an equidigital number, since it uses as much as digits as its factorization.

1391281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 432, while the sum is 25.

The square root of 1391281 is about 1179.5257521563. The cubic root of 1391281 is about 111.6361759281.

It can be divided in two parts, 139128 and 1, that added together give a square (139129 = 373²).

The spelling of 1391281 in words is "one million, three hundred ninety-one thousand, two hundred eighty-one".