645509434212864 has 1440 divisors, whose sum is σ = 2199153008532480. Its totient is φ = 181026880487424.

The previous prime is 645509434212829. The next prime is 645509434212967. The reversal of 645509434212864 is 468212434905546.

645509434212864 is a `hidden beast` number, since 6 + 4 + 5 + 5 + 0 + 9 + 4 + 342 + 1 + 286 + 4 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 142843421997 + ... + 142843426515.

Almost surely, 2^{645509434212864} is an apocalyptic number.

645509434212864 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 645509434212864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1099576504266240).

645509434212864 is an abundant number, since it is smaller than the sum of its proper divisors (1553643574319616).

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

645509434212864 is a wasteful number, since it uses less digits than its factorization.

645509434212864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4850 (or 4814 counting only the distinct ones).

The product of its (nonzero) digits is 199065600, while the sum is 63.

The spelling of 645509434212864 in words is "six hundred forty-five trillion, five hundred nine billion, four hundred thirty-four million, two hundred twelve thousand, eight hundred sixty-four".