644383407 has 8 divisors (see below), whose sum is σ = 868831920. Its totient is φ = 424761920.

The previous prime is 644383357. The next prime is 644383447. The reversal of 644383407 is 704383446.

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 644383407 - 2¹⁵ = 644350639 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644383447) 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, 1206444 + ... + 1206977.

It is an arithmetic number, because the mean of its divisors is an integer number (108603990).

Almost surely, 2^644383407 is an apocalyptic number.

644383407 is a deficient number, since it is larger than the sum of its proper divisors (224448513).

644383407 is a wasteful number, since it uses less digits than its factorization.

644383407 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2413513.

The product of its (nonzero) digits is 193536, while the sum is 39.

The square root of 644383407 is about 25384.7081330473. The cubic root of 644383407 is about 863.7368521423.

Adding to 644383407 its sum of digits (39), we get a palindrome (644383446).

The spelling of 644383407 in words is "six hundred forty-four million, three hundred eighty-three thousand, four hundred seven".