645180660 has 96 divisors (see below), whose sum is σ = 2045191680. Its totient is φ = 168794496.

The previous prime is 645180647. The next prime is 645180671. The reversal of 645180660 is 66081546.

645180660 is a `hidden beast` number, since 645 + 1 + 8 + 0 + 6 + 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 31 ways as a sum of consecutive naturals, for example, 17349 + ... + 39891.

It is an arithmetic number, because the mean of its divisors is an integer number (21304080).

Almost surely, 2^645180660 is an apocalyptic number.

645180660 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 645180660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1022595840).

645180660 is an abundant number, since it is smaller than the sum of its proper divisors (1400011020).

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

645180660 is a wasteful number, since it uses less digits than its factorization.

645180660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22614 (or 22606 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The square root of 645180660 is about 25400.4066896575. The cubic root of 645180660 is about 864.0929201762.

The spelling of 645180660 in words is "six hundred forty-five million, one hundred eighty thousand, six hundred sixty".