644427145 has 8 divisors (see below), whose sum is σ = 773515656. Its totient is φ = 515406336.

The previous prime is 644427139. The next prime is 644427191. The reversal of 644427145 is 541724446.

It can be written as a sum of positive squares in 4 ways, for example, as 30824704 + 613602441 = 5552^2 + 24771^2 .

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 644427145 - 2¹¹ = 644425097 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7129 + ... + 36601.

It is an arithmetic number, because the mean of its divisors is an integer number (96689457).

Almost surely, 2^644427145 is an apocalyptic number.

It is an amenable number.

644427145 is a deficient number, since it is larger than the sum of its proper divisors (129088511).

644427145 is a wasteful number, since it uses less digits than its factorization.

644427145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33851.

The product of its digits is 107520, while the sum is 37.

The square root of 644427145 is about 25385.5696213420. The cubic root of 644427145 is about 863.7563939593.

The spelling of 644427145 in words is "six hundred forty-four million, four hundred twenty-seven thousand, one hundred forty-five".