645027840 has 192 divisors, whose sum is σ = 2293855200. Its totient is φ = 171933696.

The previous prime is 645027839. The next prime is 645027857. The reversal of 645027840 is 48720546.

645027840 is a `hidden beast` number, since 645 + 0 + 2 + 7 + 8 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 645027795 and 645027804.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 275314 + ... + 277646.

Almost surely, 2^645027840 is an apocalyptic number.

645027840 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 645027840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1146927600).

645027840 is an abundant number, since it is smaller than the sum of its proper divisors (1648827360).

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

645027840 is a wasteful number, since it uses less digits than its factorization.

645027840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2369 (or 2343 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 36.

The square root of 645027840 is about 25397.3982919511. The cubic root of 645027840 is about 864.0246906524.

The spelling of 645027840 in words is "six hundred forty-five million, twenty-seven thousand, eight hundred forty".