6551817221 has 8 divisors (see below), whose sum is σ = 6956127360. Its totient is φ = 6149608128.

The previous prime is 6551817211. The next prime is 6551817241. The reversal of 6551817221 is 1227181556.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6551817221 - 2¹⁰ = 6551816197 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6551817211) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 518831 + ... + 531308.

It is an arithmetic number, because the mean of its divisors is an integer number (869515920).

Almost surely, 2^6551817221 is an apocalyptic number.

It is an amenable number.

6551817221 is a deficient number, since it is larger than the sum of its proper divisors (404310139).

6551817221 is a wasteful number, since it uses less digits than its factorization.

6551817221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1050523.

The product of its digits is 33600, while the sum is 38.

The square root of 6551817221 is about 80943.2963314443. The cubic root of 6551817221 is about 1871.2016470468.

Adding to 6551817221 its reverse (1227181556), we get a palindrome (7778998777).

The spelling of 6551817221 in words is "six billion, five hundred fifty-one million, eight hundred seventeen thousand, two hundred twenty-one".