645871786560 has 3360 divisors, whose sum is σ = 3252308269056. Its totient is φ = 118244966400.

The previous prime is 645871786517. The next prime is 645871786579. The reversal of 645871786560 is 65687178546.

645871786560 is a `hidden beast` number, since 6 + 4 + 58 + 7 + 17 + 8 + 6 + 560 = 666.

It is a tau number, because it is divible by the number of its divisors (3360).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 479 ways as a sum of consecutive naturals, for example, 8847558684 + ... + 8847558756.

Almost surely, 2^645871786560 is an apocalyptic number.

645871786560 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 645871786560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1626154134528).

645871786560 is an abundant number, since it is smaller than the sum of its proper divisors (2606436482496).

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

645871786560 is a wasteful number, since it uses less digits than its factorization.

645871786560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175 (or 145 counting only the distinct ones).

The product of its (nonzero) digits is 67737600, while the sum is 63.

The spelling of 645871786560 in words is "six hundred forty-five billion, eight hundred seventy-one million, seven hundred eighty-six thousand, five hundred sixty".