641551680 has 504 divisors, whose sum is σ = 2782555776. Its totient is φ = 132802560.

The previous prime is 641551649. The next prime is 641551699. The reversal of 641551680 is 86155146.

641551680 is a `hidden beast` number, since 6 + 41 + 551 + 68 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (504).

It is a super-2 number, since 2×641551680² = 823177116221644800, which contains 22 as substring.

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

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 2439229 + ... + 2439491.

It is an arithmetic number, because the mean of its divisors is an integer number (5520944).

Almost surely, 2^641551680 is an apocalyptic number.

641551680 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 641551680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1391277888).

641551680 is an abundant number, since it is smaller than the sum of its proper divisors (2141004096).

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

641551680 is a wasteful number, since it uses less digits than its factorization.

641551680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 315 (or 291 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 36.

The square root of 641551680 is about 25328.8704840938. The cubic root of 641551680 is about 862.4697708372.

The spelling of 641551680 in words is "six hundred forty-one million, five hundred fifty-one thousand, six hundred eighty".