6659720613 has 80 divisors (see below), whose sum is σ = 12575713920. Its totient is φ = 3417738624.

The previous prime is 6659720593. The next prime is 6659720621. The reversal of 6659720613 is 3160279566.

6659720613 is a `hidden beast` number, since 6 + 6 + 5 + 9 + 7 + 20 + 613 = 666.

It is not a de Polignac number, because 6659720613 - 2¹⁰ = 6659719589 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6659720623) 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 79 ways as a sum of consecutive naturals, for example, 260518 + ... + 284936.

It is an arithmetic number, because the mean of its divisors is an integer number (157196424).

Almost surely, 2^6659720613 is an apocalyptic number.

6659720613 is a gapful number since it is divisible by the number (63) formed by its first and last digit.

It is an amenable number.

6659720613 is a deficient number, since it is larger than the sum of its proper divisors (5915993307).

6659720613 is a wasteful number, since it uses less digits than its factorization.

6659720613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24488 (or 24479 counting only the distinct ones).

The product of its (nonzero) digits is 408240, while the sum is 45.

The square root of 6659720613 is about 81607.1112893968. Note that the first 3 decimals coincide. The cubic root of 6659720613 is about 1881.4181819407.

The spelling of 6659720613 in words is "six billion, six hundred fifty-nine million, seven hundred twenty thousand, six hundred thirteen".