641646720 has 768 divisors, whose sum is σ = 2806876800. Its totient is φ = 132710400.

The previous prime is 641646697. The next prime is 641646751. The reversal of 641646720 is 27646146.

641646720 is a `hidden beast` number, since 6 + 4 + 1 + 646 + 7 + 2 + 0 = 666.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 15649900 + ... + 15649940.

Almost surely, 2^641646720 is an apocalyptic number.

641646720 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 641646720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1403438400).

641646720 is an abundant number, since it is smaller than the sum of its proper divisors (2165230080).

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

641646720 is a wasteful number, since it uses less digits than its factorization.

641646720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109 (or 94 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 36.

The square root of 641646720 is about 25330.7465345970. The cubic root of 641646720 is about 862.5123577309.

The spelling of 641646720 in words is "six hundred forty-one million, six hundred forty-six thousand, seven hundred twenty".