6639687549 has 24 divisors (see below), whose sum is σ = 10494198624. Its totient is φ = 4011876000.

The previous prime is 6639687511. The next prime is 6639687563. The reversal of 6639687549 is 9457869366.

6639687549 is a `hidden beast` number, since 6 + 6 + 3 + 9 + 6 + 87 + 549 = 666.

It is not a de Polignac number, because 6639687549 - 2⁷ = 6639687421 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6639687599) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 68542 + ... + 134079.

It is an arithmetic number, because the mean of its divisors is an integer number (437258276).

Almost surely, 2^6639687549 is an apocalyptic number.

It is an amenable number.

6639687549 is a deficient number, since it is larger than the sum of its proper divisors (3854511075).

6639687549 is a wasteful number, since it uses less digits than its factorization.

6639687549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202969 (or 202966 counting only the distinct ones).

The product of its digits is 58786560, while the sum is 63.

The square root of 6639687549 is about 81484.2779252538. The cubic root of 6639687549 is about 1879.5297930937.

The spelling of 6639687549 in words is "six billion, six hundred thirty-nine million, six hundred eighty-seven thousand, five hundred forty-nine".