646785900 has 108 divisors (see below), whose sum is σ = 2082213952. Its totient is φ = 167806080.

The previous prime is 646785899. The next prime is 646785911. The reversal of 646785900 is 9587646.

646785900 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 23589 + ... + 43011.

Almost surely, 2^646785900 is an apocalyptic number.

646785900 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 646785900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1041106976).

646785900 is an abundant number, since it is smaller than the sum of its proper divisors (1435428052).

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

646785900 is a wasteful number, since it uses less digits than its factorization.

646785900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19480 (or 19470 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The square root of 646785900 is about 25431.9857659602. The cubic root of 646785900 is about 864.8089613420.

The spelling of 646785900 in words is "six hundred forty-six million, seven hundred eighty-five thousand, nine hundred".