6640739228 has 24 divisors (see below), whose sum is σ = 12144582912. Its totient is φ = 3174144624.

The previous prime is 6640739221. The next prime is 6640739293. The reversal of 6640739228 is 8229370466.

It is a Harshad number since it is a multiple of its sum of digits (47).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6640739221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 402650 + ... + 418817.

It is an arithmetic number, because the mean of its divisors is an integer number (506024288).

Almost surely, 2^6640739228 is an apocalyptic number.

It is an amenable number.

6640739228 is a deficient number, since it is larger than the sum of its proper divisors (5503843684).

6640739228 is a wasteful number, since it uses less digits than its factorization.

6640739228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 821561 (or 821559 counting only the distinct ones).

The product of its (nonzero) digits is 870912, while the sum is 47.

The square root of 6640739228 is about 81490.7309330331. The cubic root of 6640739228 is about 1879.6290225451.

The spelling of 6640739228 in words is "six billion, six hundred forty million, seven hundred thirty-nine thousand, two hundred twenty-eight".