644613838 has 8 divisors (see below), whose sum is σ = 1054822680. Its totient is φ = 293006280.

The previous prime is 644613833. The next prime is 644613859. The reversal of 644613838 is 838316446.

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

It is a junction number, because it is equal to n+sod(n) for n = 644613794 and 644613803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644613833) 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, 14650293 + ... + 14650336.

It is an arithmetic number, because the mean of its divisors is an integer number (131852835).

Almost surely, 2^644613838 is an apocalyptic number.

644613838 is a deficient number, since it is larger than the sum of its proper divisors (410208842).

644613838 is a wasteful number, since it uses less digits than its factorization.

644613838 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29300642.

The product of its digits is 331776, while the sum is 43.

The square root of 644613838 is about 25389.2465031950. The cubic root of 644613838 is about 863.8397970788.

The spelling of 644613838 in words is "six hundred forty-four million, six hundred thirteen thousand, eight hundred thirty-eight".