6534281721 has 32 divisors (see below), whose sum is σ = 10079468928. Its totient is φ = 3721303040.

The previous prime is 6534281681. The next prime is 6534281729. The reversal of 6534281721 is 1271824356.

It is a cyclic number.

It is not a de Polignac number, because 6534281721 - 2¹¹ = 6534279673 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6534281721.

It is not an unprimeable number, because it can be changed into a prime (6534281729) 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 31 ways as a sum of consecutive naturals, for example, 357415 + ... + 375251.

It is an arithmetic number, because the mean of its divisors is an integer number (314983404).

Almost surely, 2^6534281721 is an apocalyptic number.

It is an amenable number.

6534281721 is a deficient number, since it is larger than the sum of its proper divisors (3545187207).

6534281721 is a wasteful number, since it uses less digits than its factorization.

6534281721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18521.

The product of its digits is 80640, while the sum is 39.

The square root of 6534281721 is about 80834.9041008895. The cubic root of 6534281721 is about 1869.5307735356.

The spelling of 6534281721 in words is "six billion, five hundred thirty-four million, two hundred eighty-one thousand, seven hundred twenty-one".