643257028720 has 80 divisors (see below), whose sum is σ = 1543140482688. Its totient is φ = 249231974400.

The previous prime is 643257028703. The next prime is 643257028751. The reversal of 643257028720 is 27820752346.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 517131 + ... + 1246570.

Almost surely, 2^643257028720 is an apocalyptic number.

It is an amenable number.

643257028720 is an abundant number, since it is smaller than the sum of its proper divisors (899883453968).

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

643257028720 is a wasteful number, since it uses less digits than its factorization.

643257028720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1763858 (or 1763852 counting only the distinct ones).

The product of its (nonzero) digits is 1128960, while the sum is 46.

The spelling of 643257028720 in words is "six hundred forty-three billion, two hundred fifty-seven million, twenty-eight thousand, seven hundred twenty".