644612330 has 8 divisors (see below), whose sum is σ = 1160302212. Its totient is φ = 257844928.

The previous prime is 644612323. The next prime is 644612369. The reversal of 644612330 is 33216446.

It can be written as a sum of positive squares in 2 ways, for example, as 643586161 + 1026169 = 25369^2 + 1013^2 .

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

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 644612293 and 644612302.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32230607 + ... + 32230626.

Almost surely, 2^644612330 is an apocalyptic number.

644612330 is a deficient number, since it is larger than the sum of its proper divisors (515689882).

644612330 is a wasteful number, since it uses less digits than its factorization.

644612330 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64461240.

The product of its (nonzero) digits is 10368, while the sum is 29.

The square root of 644612330 is about 25389.2168055653. The cubic root of 644612330 is about 863.8391234603.

Adding to 644612330 its reverse (33216446), we get a palindrome (677828776).

The spelling of 644612330 in words is "six hundred forty-four million, six hundred twelve thousand, three hundred thirty".