644326055 has 8 divisors (see below), whose sum is σ = 789642432. Its totient is φ = 504493408.

The previous prime is 644326051. The next prime is 644326057. The reversal of 644326055 is 550623446.

It is a happy number.

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 644326055 - 2² = 644326051 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644326051) 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, 1370672 + ... + 1371141.

It is an arithmetic number, because the mean of its divisors is an integer number (98705304).

Almost surely, 2^644326055 is an apocalyptic number.

644326055 is a deficient number, since it is larger than the sum of its proper divisors (145316377).

644326055 is a wasteful number, since it uses less digits than its factorization.

644326055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2741865.

The product of its (nonzero) digits is 86400, while the sum is 35.

The square root of 644326055 is about 25383.5784514319. The cubic root of 644326055 is about 863.7112263502.

The spelling of 644326055 in words is "six hundred forty-four million, three hundred twenty-six thousand, fifty-five".