6551130721 has 4 divisors (see below), whose sum is σ = 6551676100. Its totient is φ = 6550585344.

The previous prime is 6551130671. The next prime is 6551130749. The reversal of 6551130721 is 1270311556.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2473669696 + 4077461025 = 49736^2 + 63855^2 .

It is a cyclic number.

It is not a de Polignac number, because 6551130721 - 2¹⁷ = 6550999649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6551130791) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 254256 + ... + 278833.

It is an arithmetic number, because the mean of its divisors is an integer number (1637919025).

Almost surely, 2^6551130721 is an apocalyptic number.

It is an amenable number.

6551130721 is a deficient number, since it is larger than the sum of its proper divisors (545379).

6551130721 is a wasteful number, since it uses less digits than its factorization.

6551130721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 545378.

The product of its (nonzero) digits is 6300, while the sum is 31.

The square root of 6551130721 is about 80939.0555974061. The cubic root of 6551130721 is about 1871.1362898715.

The spelling of 6551130721 in words is "six billion, five hundred fifty-one million, one hundred thirty thousand, seven hundred twenty-one".