644890740480 has 2592 divisors, whose sum is σ = 3022907247360. Its totient is φ = 130427781120.

The previous prime is 644890740467. The next prime is 644890740521. The reversal of 644890740480 is 84047098446.

644890740480 is a `hidden beast` number, since 6 + 4 + 4 + 8 + 90 + 74 + 0 + 480 = 666.

It is a tau number, because it is divible by the number of its divisors (2592).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 4922830015 + ... + 4922830145.

It is an arithmetic number, because the mean of its divisors is an integer number (1166245080).

Almost surely, 2^644890740480 is an apocalyptic number.

644890740480 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 644890740480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1511453623680).

644890740480 is an abundant number, since it is smaller than the sum of its proper divisors (2378016506880).

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

644890740480 is a wasteful number, since it uses less digits than its factorization.

644890740480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217 (or 184 counting only the distinct ones).

The product of its (nonzero) digits is 6193152, while the sum is 54.

The spelling of 644890740480 in words is "six hundred forty-four billion, eight hundred ninety million, seven hundred forty thousand, four hundred eighty".