646947840 has 352 divisors, whose sum is σ = 2584525824. Its totient is φ = 134184960.

The previous prime is 646947799. The next prime is 646947877. The reversal of 646947840 is 48749646.

It is a tau number, because it is divible by the number of its divisors (352).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 646947840.

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, 1182447 + ... + 1182993.

Almost surely, 2^646947840 is an apocalyptic number.

646947840 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 646947840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1292262912).

646947840 is an abundant number, since it is smaller than the sum of its proper divisors (1937577984).

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

646947840 is a wasteful number, since it uses less digits than its factorization.

646947840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 593 (or 575 counting only the distinct ones).

The product of its (nonzero) digits is 1161216, while the sum is 48.

The square root of 646947840 is about 25435.1693526896. The cubic root of 646947840 is about 864.8811312706.

The spelling of 646947840 in words is "six hundred forty-six million, nine hundred forty-seven thousand, eight hundred forty".