6651187321 has 24 divisors (see below), whose sum is σ = 7326061344. Its totient is φ = 6032785920.

The previous prime is 6651187297. The next prime is 6651187327. The reversal of 6651187321 is 1237811566.

It is a happy number.

It is not a de Polignac number, because 6651187321 - 2⁵ = 6651187289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6651187327) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 980086 + ... + 986848.

It is an arithmetic number, because the mean of its divisors is an integer number (305252556).

Almost surely, 2^6651187321 is an apocalyptic number.

It is an amenable number.

6651187321 is a deficient number, since it is larger than the sum of its proper divisors (674874023).

6651187321 is a wasteful number, since it uses less digits than its factorization.

6651187321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6921 (or 6904 counting only the distinct ones).

The product of its digits is 60480, while the sum is 40.

The square root of 6651187321 is about 81554.8117587184. The cubic root of 6651187321 is about 1880.6142666990.

Adding to 6651187321 its reverse (1237811566), we get a palindrome (7888998887).

The spelling of 6651187321 in words is "six billion, six hundred fifty-one million, one hundred eighty-seven thousand, three hundred twenty-one".