644523480 has 336 divisors, whose sum is σ = 2344353840. Its totient is φ = 159096960.

The previous prime is 644523479. The next prime is 644523547. The reversal of 644523480 is 84325446.

644523480 is a `hidden beast` number, since 644 + 5 + 2 + 3 + 4 + 8 + 0 = 666.

644523480 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 83 ways as a sum of consecutive naturals, for example, 20791065 + ... + 20791095.

Almost surely, 2^644523480 is an apocalyptic number.

644523480 is a gapful number since it is divisible by the number (60) 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 644523480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1172176920).

644523480 is an abundant number, since it is smaller than the sum of its proper divisors (1699830360).

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

644523480 is a wasteful number, since it uses less digits than its factorization.

644523480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114 (or 64 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 36.

The square root of 644523480 is about 25387.4669866846. The cubic root of 644523480 is about 863.7994326109.

The spelling of 644523480 in words is "six hundred forty-four million, five hundred twenty-three thousand, four hundred eighty".