644315401 has 4 divisors (see below), whose sum is σ = 644717952. Its totient is φ = 643912852.

The previous prime is 644315393. The next prime is 644315407. The reversal of 644315401 is 104513446.

644315401 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 644315401 - 2³ = 644315393 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 644315401.

It is not an unprimeable number, because it can be changed into a prime (644315407) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 198865 + ... + 202078.

It is an arithmetic number, because the mean of its divisors is an integer number (161179488).

Almost surely, 2^644315401 is an apocalyptic number.

It is an amenable number.

644315401 is a deficient number, since it is larger than the sum of its proper divisors (402551).

644315401 is a wasteful number, since it uses less digits than its factorization.

644315401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 402550.

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 644315401 is about 25383.3685904767. The cubic root of 644315401 is about 863.7064658049.

Adding to 644315401 its reverse (104513446), we get a palindrome (748828847).

The spelling of 644315401 in words is "six hundred forty-four million, three hundred fifteen thousand, four hundred one".