6658391 has 4 divisors (see below), whose sum is σ = 6666000. Its totient is φ = 6650784.

The previous prime is 6658369. The next prime is 6658411. The reversal of 6658391 is 1938566.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 6658391 - 2¹⁰ = 6657367 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 (6658321) 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 3 ways as a sum of consecutive naturals, for example, 2291 + ... + 4308.

It is an arithmetic number, because the mean of its divisors is an integer number (1666500).

Almost surely, 2^6658391 is an apocalyptic number.

6658391 is a deficient number, since it is larger than the sum of its proper divisors (7609).

6658391 is a wasteful number, since it uses less digits than its factorization.

6658391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7608.

The product of its digits is 38880, while the sum is 38.

The square root of 6658391 is about 2580.3858238643. The cubic root of 6658391 is about 188.1292965248.

The spelling of 6658391 in words is "six million, six hundred fifty-eight thousand, three hundred ninety-one".