646171680 has 192 divisors, whose sum is σ = 2537837568. Its totient is φ = 134261760.

The previous prime is 646171679. The next prime is 646171697. The reversal of 646171680 is 86171646.

It is a happy number.

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 31 ways as a sum of consecutive naturals, for example, 28219 + ... + 45701.

It is an arithmetic number, because the mean of its divisors is an integer number (13217904).

Almost surely, 2^646171680 is an apocalyptic number.

646171680 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 646171680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1268918784).

646171680 is an abundant number, since it is smaller than the sum of its proper divisors (1891665888).

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

646171680 is a wasteful number, since it uses less digits than its factorization.

646171680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17519 (or 17511 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 39.

The square root of 646171680 is about 25419.9071595472. The cubic root of 646171680 is about 864.5351194649.

The spelling of 646171680 in words is "six hundred forty-six million, one hundred seventy-one thousand, six hundred eighty".