6551999 has 4 divisors (see below), whose sum is σ = 6777960. Its totient is φ = 6326040.

The previous prime is 6551989. The next prime is 6552001. The reversal of 6551999 is 9991556.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 6551999 - 2⁴ = 6551983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6551959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 112937 + ... + 112994.

It is an arithmetic number, because the mean of its divisors is an integer number (1694490).

Almost surely, 2^6551999 is an apocalyptic number.

6551999 is a deficient number, since it is larger than the sum of its proper divisors (225961).

6551999 is a wasteful number, since it uses less digits than its factorization.

6551999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 225960.

The product of its digits is 109350, while the sum is 44.

The square root of 6551999 is about 2559.6872855878. The cubic root of 6551999 is about 187.1218952272.

The spelling of 6551999 in words is "six million, five hundred fifty-one thousand, nine hundred ninety-nine".