6405989 has 2 divisors, whose sum is σ = 6405990. Its totient is φ = 6405988.

The previous prime is 6405979. The next prime is 6406051. The reversal of 6405989 is 9895046.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5712100 + 693889 = 2390^2 + 833^2 .

It is a cyclic number.

It is not a de Polignac number, because 6405989 - 2⁸ = 6405733 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6405929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3202994 + 3202995.

It is an arithmetic number, because the mean of its divisors is an integer number (3202995).

Almost surely, 2^6405989 is an apocalyptic number.

It is an amenable number.

6405989 is a deficient number, since it is larger than the sum of its proper divisors (1).

6405989 is an equidigital number, since it uses as much as digits as its factorization.

6405989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 77760, while the sum is 41.

The square root of 6405989 is about 2531.0055314045. The cubic root of 6405989 is about 185.7214487798.

The spelling of 6405989 in words is "six million, four hundred five thousand, nine hundred eighty-nine".