646406728 has 32 divisors (see below), whose sum is σ = 1324091520. Its totient is φ = 293400000.

The previous prime is 646406713. The next prime is 646406737. The reversal of 646406728 is 827604646.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 61198 + ... + 70978.

It is an arithmetic number, because the mean of its divisors is an integer number (41377860).

Almost surely, 2^646406728 is an apocalyptic number.

It is an amenable number.

646406728 is an abundant number, since it is smaller than the sum of its proper divisors (677684792).

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

646406728 is a wasteful number, since it uses less digits than its factorization.

646406728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10549 (or 10545 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 43.

The square root of 646406728 is about 25424.5300448209. The cubic root of 646406728 is about 864.6399330012.

The spelling of 646406728 in words is "six hundred forty-six million, four hundred six thousand, seven hundred twenty-eight".