644190144 has 84 divisors (see below), whose sum is σ = 1845707256. Its totient is φ = 198202368.

The previous prime is 644190097. The next prime is 644190149. The reversal of 644190144 is 441091446.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644190149) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22522 + ... + 42374.

Almost surely, 2^644190144 is an apocalyptic number.

644190144 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644190144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (922853628).

644190144 is an abundant number, since it is smaller than the sum of its proper divisors (1201517112).

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

644190144 is a wasteful number, since it uses less digits than its factorization.

644190144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19894 (or 19871 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 33.

The square root of 644190144 is about 25380.9011660343. The cubic root of 644190144 is about 863.6504930666.

The spelling of 644190144 in words is "six hundred forty-four million, one hundred ninety thousand, one hundred forty-four".