6643898 has 4 divisors (see below), whose sum is σ = 9965850. Its totient is φ = 3321948.

The previous prime is 6643891. The next prime is 6643907. The reversal of 6643898 is 8983466.

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

It can be written as a sum of positive squares in only one way, i.e., 6135529 + 508369 = 2477^2 + 713^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (6643891) 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 as a sum of consecutive naturals, namely, 1660973 + ... + 1660976.

Almost surely, 2^6643898 is an apocalyptic number.

6643898 is a deficient number, since it is larger than the sum of its proper divisors (3321952).

6643898 is a wasteful number, since it uses less digits than its factorization.

6643898 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3321951.

The product of its digits is 248832, while the sum is 44.

The square root of 6643898 is about 2577.5759930601. The cubic root of 6643898 is about 187.9927000334.

The spelling of 6643898 in words is "six million, six hundred forty-three thousand, eight hundred ninety-eight".