1321399 has 2 divisors, whose sum is σ = 1321400. Its totient is φ = 1321398.

The previous prime is 1321391. The next prime is 1321409. The reversal of 1321399 is 9931231.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1321399 - 2³ = 1321391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1321391) 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, 660699 + 660700.

It is an arithmetic number, because the mean of its divisors is an integer number (660700).

2^1321399 is an apocalyptic number.

1321399 is a deficient number, since it is larger than the sum of its proper divisors (1).

1321399 is an equidigital number, since it uses as much as digits as its factorization.

1321399 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1458, while the sum is 28.

The square root of 1321399 is about 1149.5212046761. The cubic root of 1321399 is about 109.7348711251.

It can be divided in two parts, 13 and 21399, that added together give a palindrome (21412).

The spelling of 1321399 in words is "one million, three hundred twenty-one thousand, three hundred ninety-nine".