1320399 has 12 divisors (see below), whose sum is σ = 1973400. Its totient is φ = 849744.

The previous prime is 1320391. The next prime is 1320409. The reversal of 1320399 is 9930231.

It is not a de Polignac number, because 1320399 - 2³ = 1320391 is a prime.

1320399 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1320391) 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 in 11 ways as a sum of consecutive naturals, for example, 2269 + ... + 2790.

It is an arithmetic number, because the mean of its divisors is an integer number (164450).

2^1320399 is an apocalyptic number.

1320399 is a deficient number, since it is larger than the sum of its proper divisors (653001).

1320399 is a wasteful number, since it uses less digits than its factorization.

1320399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5094 (or 5091 counting only the distinct ones).

The product of its (nonzero) digits is 1458, while the sum is 27.

The square root of 1320399 is about 1149.0861586496. The cubic root of 1320399 is about 109.7071826514.

It can be divided in two parts, 1 and 320399, that added together give a triangular number (320400 = T₈₀₀).

The spelling of 1320399 in words is "one million, three hundred twenty thousand, three hundred ninety-nine".