1320999 has 4 divisors (see below), whose sum is σ = 1761336. Its totient is φ = 880664.

The previous prime is 1320983. The next prime is 1321007. The reversal of 1320999 is 9990231.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1320999 - 2⁴ = 1320983 is a prime.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1320929) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 220164 + ... + 220169.

It is an arithmetic number, because the mean of its divisors is an integer number (440334).

2^1320999 is an apocalyptic number.

1320999 is a deficient number, since it is larger than the sum of its proper divisors (440337).

1320999 is an equidigital number, since it uses as much as digits as its factorization.

1320999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 440336.

The product of its (nonzero) digits is 4374, while the sum is 33.

The square root of 1320999 is about 1149.3472060261. The cubic root of 1320999 is about 109.7237974125.

It can be divided in two parts, 13 and 20999, that added together give a palindrome (21012).

The spelling of 1320999 in words is "one million, three hundred twenty thousand, nine hundred ninety-nine".