6747208856521 has 21 divisors (see below), whose sum is σ = 7872773692071. Its totient is φ = 5782558200552.

The previous prime is 6747208856467. The next prime is 6747208856537. The reversal of 6747208856521 is 1256588027476.

The square root of 6747208856521 is 2597539.

It is a perfect power (a square), and thus also a powerful number.

6747208856521 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 6732961092025 + 14247764496 = 2594795^2 + 119364^2 .

It is not a de Polignac number, because 6747208856521 - 2¹¹ = 6747208854473 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6747208856521.

It is not an unprimeable number, because it can be changed into a prime (6747208856621) by changing a digit.

It is a polite number, since it can be written in 20 ways as a sum of consecutive naturals, for example, 890952091 + ... + 890959663.

Almost surely, 2^{6747208856521} is an apocalyptic number.

6747208856521 is the 2597539-th square number.

6747208856521 is the 1298770-th centered octagonal number.

It is an amenable number.

6747208856521 is a deficient number, since it is larger than the sum of its proper divisors (1125564835550).

6747208856521 is an frugal number, since it uses more digits than its factorization.

6747208856521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15188 (or 7580 counting only the distinct ones).

The product of its (nonzero) digits is 45158400, while the sum is 61.

The spelling of 6747208856521 in words is "six trillion, seven hundred forty-seven billion, two hundred eight million, eight hundred fifty-six thousand, five hundred twenty-one".