6547799921 has 4 divisors (see below), whose sum is σ = 7051476852. Its totient is φ = 6044122992.

The previous prime is 6547799891. The next prime is 6547799957. The reversal of 6547799921 is 1299977456.

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 1032658225 + 5515141696 = 32135^2 + 74264^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6547799921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6547799521) 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 3 ways as a sum of consecutive naturals, for example, 251838446 + ... + 251838471.

It is an arithmetic number, because the mean of its divisors is an integer number (1762869213).

Almost surely, 2^6547799921 is an apocalyptic number.

It is an amenable number.

6547799921 is a deficient number, since it is larger than the sum of its proper divisors (503676931).

6547799921 is a wasteful number, since it uses less digits than its factorization.

6547799921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 503676930.

The product of its digits is 8573040, while the sum is 59.

The square root of 6547799921 is about 80918.4770061820. The cubic root of 6547799921 is about 1870.8191213519.

The spelling of 6547799921 in words is "six billion, five hundred forty-seven million, seven hundred ninety-nine thousand, nine hundred twenty-one".