644648038 has 16 divisors (see below), whose sum is σ = 999020160. Its totient is φ = 311659200.

The previous prime is 644648029. The next prime is 644648051. The reversal of 644648038 is 830846446.

It is a junction number, because it is equal to n+sod(n) for n = 644647985 and 644648003.

It is a congruent 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, 81858 + ... + 89386.

It is an arithmetic number, because the mean of its divisors is an integer number (62438760).

Almost surely, 2^644648038 is an apocalyptic number.

644648038 is a deficient number, since it is larger than the sum of its proper divisors (354372122).

644648038 is a wasteful number, since it uses less digits than its factorization.

644648038 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8943.

The product of its (nonzero) digits is 442368, while the sum is 43.

The square root of 644648038 is about 25389.9200077511. The cubic root of 644648038 is about 863.8550738212.

The spelling of 644648038 in words is "six hundred forty-four million, six hundred forty-eight thousand, thirty-eight".