1331999 has 8 divisors (see below), whose sum is σ = 1438560. Its totient is φ = 1229536.

The previous prime is 1331989. The next prime is 1332017. The reversal of 1331999 is 9991331.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1331999 - 2¹² = 1327903 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1331929) 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 7 ways as a sum of consecutive naturals, for example, 332 + ... + 1665.

It is an arithmetic number, because the mean of its divisors is an integer number (179820).

2^1331999 is an apocalyptic number.

1331999 is a deficient number, since it is larger than the sum of its proper divisors (106561).

1331999 is a wasteful number, since it uses less digits than its factorization.

1331999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2049.

The product of its digits is 6561, while the sum is 35.

The square root of 1331999 is about 1154.1226104708. The cubic root of 1331999 is about 110.0275137787.

The spelling of 1331999 in words is "one million, three hundred thirty-one thousand, nine hundred ninety-nine".