6440999 has 2 divisors, whose sum is σ = 6441000. Its totient is φ = 6440998.

The previous prime is 6440983. The next prime is 6441031. The reversal of 6440999 is 9990446.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6440999 - 2⁴ = 6440983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6440939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3220499 + 3220500.

It is an arithmetic number, because the mean of its divisors is an integer number (3220500).

Almost surely, 2^6440999 is an apocalyptic number.

6440999 is a deficient number, since it is larger than the sum of its proper divisors (1).

6440999 is an equidigital number, since it uses as much as digits as its factorization.

6440999 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 69984, while the sum is 41.

The square root of 6440999 is about 2537.9123310312. The cubic root of 6440999 is about 186.0591691356.

The spelling of 6440999 in words is "six million, four hundred forty thousand, nine hundred ninety-nine".