644854560 has 384 divisors, whose sum is σ = 2471067648. Its totient is φ = 138240000.

The previous prime is 644854549. The next prime is 644854571. The reversal of 644854560 is 65458446.

644854560 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (644854549) and next prime (644854571).

It is a Harshad number since it is a multiple of its sum of digits (42).

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, 4270485 + ... + 4270635.

It is an arithmetic number, because the mean of its divisors is an integer number (6435072).

Almost surely, 2^644854560 is an apocalyptic number.

644854560 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 644854560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1235533824).

644854560 is an abundant number, since it is smaller than the sum of its proper divisors (1826213088).

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

644854560 is a wasteful number, since it uses less digits than its factorization.

644854560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 248 (or 240 counting only the distinct ones).

The product of its (nonzero) digits is 460800, while the sum is 42.

The square root of 644854560 is about 25393.9866897657. The cubic root of 644854560 is about 863.9473133167.

The spelling of 644854560 in words is "six hundred forty-four million, eight hundred fifty-four thousand, five hundred sixty".