6649999 has 2 divisors, whose sum is σ = 6650000. Its totient is φ = 6649998.

The previous prime is 6649919. The next prime is 6650003. The reversal of 6649999 is 9999466.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6649999 - 2⁷ = 6649871 is a prime.

6649999 is a modest number, since divided by 9999 gives 664 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6649919) 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, 3324999 + 3325000.

It is an arithmetic number, because the mean of its divisors is an integer number (3325000).

Almost surely, 2^6649999 is an apocalyptic number.

6649999 is a deficient number, since it is larger than the sum of its proper divisors (1).

6649999 is an equidigital number, since it uses as much as digits as its factorization.

6649999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 944784, while the sum is 52.

The square root of 6649999 is about 2578.7591977538. The cubic root of 6649999 is about 188.0502261307.

The spelling of 6649999 in words is "six million, six hundred forty-nine thousand, nine hundred ninety-nine".