1986989 has 2 divisors, whose sum is σ = 1986990. Its totient is φ = 1986988.

The previous prime is 1986967. The next prime is 1986991. The reversal of 1986989 is 9896891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1768900 + 218089 = 1330^2 + 467^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1986989 is a prime.

It is a super-2 number, since 2×1986989² = 7896250572242, which contains 22 as substring.

Together with 1986991, 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 (1986949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 993494 + 993495.

It is an arithmetic number, because the mean of its divisors is an integer number (993495).

2^1986989 is an apocalyptic number.

It is an amenable number.

1986989 is a deficient number, since it is larger than the sum of its proper divisors (1).

1986989 is an equidigital number, since it uses as much as digits as its factorization.

1986989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 279936, while the sum is 50.

The square root of 1986989 is about 1409.6059733131. The cubic root of 1986989 is about 125.7182964949.

The spelling of 1986989 in words is "one million, nine hundred eighty-six thousand, nine hundred eighty-nine".