6720779640 has 64 divisors (see below), whose sum is σ = 20417587200. Its totient is φ = 1769519232.

The previous prime is 6720779543. The next prime is 6720779657. The reversal of 6720779640 is 469770276.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 6720779640.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 344992 + ... + 363951.

It is an arithmetic number, because the mean of its divisors is an integer number (319024800).

Almost surely, 2^6720779640 is an apocalyptic number.

6720779640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

6720779640 is an abundant number, since it is smaller than the sum of its proper divisors (13696807560).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6720779640 is a wasteful number, since it uses less digits than its factorization.

6720779640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 709036 (or 709032 counting only the distinct ones).

The product of its (nonzero) digits is 889056, while the sum is 48.

The square root of 6720779640 is about 81980.3613068398. The cubic root of 6720779640 is about 1887.1505675374.

The spelling of 6720779640 in words is "six billion, seven hundred twenty million, seven hundred seventy-nine thousand, six hundred forty".