645115209984 has 648 divisors, whose sum is σ = 2222756303040. Its totient is φ = 176251576320.

The previous prime is 645115209983. The next prime is 645115210081. The reversal of 645115209984 is 489902511546.

645115209984 is a `hidden beast` number, since 6 + 451 + 1 + 5 + 20 + 99 + 84 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 645115209984.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645115209983) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 1658393662 + ... + 1658394050.

It is an arithmetic number, because the mean of its divisors is an integer number (3430179480).

Almost surely, 2^645115209984 is an apocalyptic number.

645115209984 is a gapful number since it is divisible by the number (64) 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 645115209984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1111378151520).

645115209984 is an abundant number, since it is smaller than the sum of its proper divisors (1577641093056).

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

645115209984 is a wasteful number, since it uses less digits than its factorization.

645115209984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 587 (or 539 counting only the distinct ones).

The product of its (nonzero) digits is 3110400, while the sum is 54.

The spelling of 645115209984 in words is "six hundred forty-five billion, one hundred fifteen million, two hundred nine thousand, nine hundred eighty-four".