6638889 has 4 divisors (see below), whose sum is σ = 8851856. Its totient is φ = 4425924.

The previous prime is 6638851. The next prime is 6638893. The reversal of 6638889 is 9888366.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 6638889 - 2⁸ = 6638633 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6638689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1106479 + ... + 1106484.

It is an arithmetic number, because the mean of its divisors is an integer number (2212964).

Almost surely, 2^6638889 is an apocalyptic number.

It is an amenable number.

6638889 is a deficient number, since it is larger than the sum of its proper divisors (2212967).

6638889 is a wasteful number, since it uses less digits than its factorization.

6638889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2212966.

The product of its digits is 497664, while the sum is 48.

The square root of 6638889 is about 2576.6041605183. The cubic root of 6638889 is about 187.9454440310.

The spelling of 6638889 in words is "six million, six hundred thirty-eight thousand, eight hundred eighty-nine".