1995989 has 2 divisors, whose sum is σ = 1995990. Its totient is φ = 1995988.

The previous prime is 1995979. The next prime is 1995991. The reversal of 1995989 is 9895991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1060900 + 935089 = 1030^2 + 967^2 .

It is a cyclic number.

It is not a de Polignac number, because 1995989 - 2¹² = 1991893 is a prime.

Together with 1995991, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1995979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 997994 + 997995.

It is an arithmetic number, because the mean of its divisors is an integer number (997995).

2^1995989 is an apocalyptic number.

It is an amenable number.

1995989 is a deficient number, since it is larger than the sum of its proper divisors (1).

1995989 is an equidigital number, since it uses as much as digits as its factorization.

1995989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 262440, while the sum is 50.

The square root of 1995989 is about 1412.7947480084. The cubic root of 1995989 is about 125.9078228996.

The spelling of 1995989 in words is "one million, nine hundred ninety-five thousand, nine hundred eighty-nine".