656640000 has 480 divisors, whose sum is σ = 2558556000. Its totient is φ = 165888000.

The previous prime is 656639987. The next prime is 656640001. The reversal of 656640000 is 46656.

656640000 is a `hidden beast` number, since 656 + 6 + 4 + 0 + 0 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (480).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (656640001) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 34559991 + ... + 34560009.

It is an arithmetic number, because the mean of its divisors is an integer number (5330325).

Almost surely, 2^656640000 is an apocalyptic number.

656640000 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 656640000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1279278000).

656640000 is an abundant number, since it is smaller than the sum of its proper divisors (1901916000).

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

656640000 is an equidigital number, since it uses as much as digits as its factorization.

656640000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70 (or 29 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 656640000 is about 25624.9878048751. The cubic root of 656640000 is about 869.1787732130.

Adding to 656640000 its reverse (46656), we get a palindrome (656686656).

The spelling of 656640000 in words is "six hundred fifty-six million, six hundred forty thousand".