641494656 has 384 divisors, whose sum is σ = 2199674880. Its totient is φ = 177408000.

The previous prime is 641494603. The next prime is 641494657. The reversal of 641494656 is 656494146.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (384).

It is not an unprimeable number, because it can be changed into a prime (641494657) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 9035101 + ... + 9035171.

It is an arithmetic number, because the mean of its divisors is an integer number (5728320).

Almost surely, 2^641494656 is an apocalyptic number.

641494656 is a gapful number since it is divisible by the number (66) 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 641494656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1099837440).

641494656 is an abundant number, since it is smaller than the sum of its proper divisors (1558180224).

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

641494656 is a wasteful number, since it uses less digits than its factorization.

641494656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156 (or 141 counting only the distinct ones).

The product of its digits is 622080, while the sum is 45.

The square root of 641494656 is about 25327.7447870907. The cubic root of 641494656 is about 862.4442166821. Note that the first 3 decimals are identical.

The spelling of 641494656 in words is "six hundred forty-one million, four hundred ninety-four thousand, six hundred fifty-six".