646873081920 has 1344 divisors, whose sum is σ = 2696016960000. Its totient is φ = 140630556672.

The previous prime is 646873081873. The next prime is 646873081949. The reversal of 646873081920 is 29180378646.

It is a super-3 number, since 3×646873081920³ (a number of 36 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

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 191 ways as a sum of consecutive naturals, for example, 1801874701 + ... + 1801875059.

It is an arithmetic number, because the mean of its divisors is an integer number (2005965000).

Almost surely, 2^646873081920 is an apocalyptic number.

646873081920 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 646873081920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1348008480000).

646873081920 is an abundant number, since it is smaller than the sum of its proper divisors (2049143878080).

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

646873081920 is a wasteful number, since it uses less digits than its factorization.

646873081920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 580 (or 567 counting only the distinct ones).

The product of its (nonzero) digits is 3483648, while the sum is 54.

The spelling of 646873081920 in words is "six hundred forty-six billion, eight hundred seventy-three million, eighty-one thousand, nine hundred twenty".