645820560 has 480 divisors, whose sum is σ = 2802320640. Its totient is φ = 133816320.

The previous prime is 645820559. The next prime is 645820573. The reversal of 645820560 is 65028546.

645820560 is a `hidden beast` number, since 645 + 8 + 2 + 0 + 5 + 6 + 0 = 666.

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 95 ways as a sum of consecutive naturals, for example, 1829344 + ... + 1829696.

It is an arithmetic number, because the mean of its divisors is an integer number (5838168).

Almost surely, 2^645820560 is an apocalyptic number.

645820560 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 645820560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1401160320).

645820560 is an abundant number, since it is smaller than the sum of its proper divisors (2156500080).

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

645820560 is a wasteful number, since it uses less digits than its factorization.

645820560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 404 (or 381 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The square root of 645820560 is about 25412.9998229253. Note that the first 3 decimals coincide. The cubic root of 645820560 is about 864.3784992871.

The spelling of 645820560 in words is "six hundred forty-five million, eight hundred twenty thousand, five hundred sixty".