1331989 has 2 divisors, whose sum is σ = 1331990. Its totient is φ = 1331988.

The previous prime is 1331987. The next prime is 1332017. The reversal of 1331989 is 9891331.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 935089 + 396900 = 967^2 + 630^2 .

It is a cyclic number.

It is not a de Polignac number, because 1331989 - 2¹ = 1331987 is a prime.

It is a super-2 number, since 2×1331989² = 3548389392242, which contains 22 as substring.

Together with 1331987, it forms a pair of twin primes.

1331989 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1331987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 665994 + 665995.

It is an arithmetic number, because the mean of its divisors is an integer number (665995).

2^1331989 is an apocalyptic number.

It is an amenable number.

1331989 is a deficient number, since it is larger than the sum of its proper divisors (1).

1331989 is an equidigital number, since it uses as much as digits as its factorization.

1331989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5832, while the sum is 34.

The square root of 1331989 is about 1154.1182781674. The cubic root of 1331989 is about 110.0272384337.

The spelling of 1331989 in words is "one million, three hundred thirty-one thousand, nine hundred eighty-nine".