6539993 has 8 divisors (see below), whose sum is σ = 6878280. Its totient is φ = 6209280.

The previous prime is 6539989. The next prime is 6540007. The reversal of 6539993 is 3999356.

It can be written as a sum of positive squares in 4 ways, for example, as 123904 + 6416089 = 352^2 + 2533^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6539993 - 2² = 6539989 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6539963) 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 in 7 ways as a sum of consecutive naturals, for example, 80 + ... + 3617.

It is an arithmetic number, because the mean of its divisors is an integer number (859785).

Almost surely, 2^6539993 is an apocalyptic number.

It is an amenable number.

6539993 is a deficient number, since it is larger than the sum of its proper divisors (338287).

6539993 is a wasteful number, since it uses less digits than its factorization.

6539993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3787.

The product of its digits is 196830, while the sum is 44.

The square root of 6539993 is about 2557.3410019002. The cubic root of 6539993 is about 187.0075301761.

The spelling of 6539993 in words is "six million, five hundred thirty-nine thousand, nine hundred ninety-three".