660887640 has 512 divisors, whose sum is σ = 2737152000. Its totient is φ = 138475008.

The previous prime is 660887627. The next prime is 660887657. The reversal of 660887640 is 46788066.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 6176467 + ... + 6176573.

It is an arithmetic number, because the mean of its divisors is an integer number (5346000).

Almost surely, 2^660887640 is an apocalyptic number.

660887640 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 660887640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1368576000).

660887640 is an abundant number, since it is smaller than the sum of its proper divisors (2076264360).

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

660887640 is a wasteful number, since it uses less digits than its factorization.

660887640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196 (or 186 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 45.

The square root of 660887640 is about 25707.7350227514. The cubic root of 660887640 is about 871.0489132314.

The spelling of 660887640 in words is "six hundred sixty million, eight hundred eighty-seven thousand, six hundred forty".