6640641838 has 4 divisors (see below), whose sum is σ = 9960962760. Its totient is φ = 3320320918.

The previous prime is 6640641769. The next prime is 6640641871. The reversal of 6640641838 is 8381460466.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1660160458 + ... + 1660160461.

It is an arithmetic number, because the mean of its divisors is an integer number (2490240690).

Almost surely, 2^6640641838 is an apocalyptic number.

6640641838 is a deficient number, since it is larger than the sum of its proper divisors (3320320922).

6640641838 is a wasteful number, since it uses less digits than its factorization.

6640641838 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3320320921.

The product of its (nonzero) digits is 663552, while the sum is 46.

The square root of 6640641838 is about 81490.1333782195. The cubic root of 6640641838 is about 1879.6198339112.

The spelling of 6640641838 in words is "six billion, six hundred forty million, six hundred forty-one thousand, eight hundred thirty-eight".