644124390 has 128 divisors (see below), whose sum is σ = 2014709760. Its totient is φ = 127899648.

The previous prime is 644124353. The next prime is 644124409. The reversal of 644124390 is 93421446.

644124390 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 39471 + ... + 53349.

It is an arithmetic number, because the mean of its divisors is an integer number (15739920).

Almost surely, 2^644124390 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644124390, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1007354880).

644124390 is an abundant number, since it is smaller than the sum of its proper divisors (1370585370).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644124390 is a wasteful number, since it uses less digits than its factorization.

644124390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13926.

The product of its (nonzero) digits is 20736, while the sum is 33.

The square root of 644124390 is about 25379.6057889007. The cubic root of 644124390 is about 863.6211071224.

The spelling of 644124390 in words is "six hundred forty-four million, one hundred twenty-four thousand, three hundred ninety".