6644320551 has 24 divisors (see below), whose sum is σ = 10807580160. Its totient is φ = 3896960400.

The previous prime is 6644320549. The next prime is 6644320583. The reversal of 6644320551 is 1550234466.

6644320551 is a `hidden beast` number, since 6 + 6 + 443 + 205 + 5 + 1 = 666.

It is not a de Polignac number, because 6644320551 - 2¹ = 6644320549 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6644320531) 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, 1079421 + ... + 1085558.

It is an arithmetic number, because the mean of its divisors is an integer number (450315840).

Almost surely, 2^6644320551 is an apocalyptic number.

6644320551 is a deficient number, since it is larger than the sum of its proper divisors (4163259609).

6644320551 is a wasteful number, since it uses less digits than its factorization.

6644320551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2165027 (or 2165024 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 36.

The square root of 6644320551 is about 81512.7017770850. The cubic root of 6644320551 is about 1879.9668538558.

The spelling of 6644320551 in words is "six billion, six hundred forty-four million, three hundred twenty thousand, five hundred fifty-one".