646781338 has 16 divisors (see below), whose sum is σ = 1114401024. Its totient is φ = 275783760.

The previous prime is 646781309. The next prime is 646781341. The reversal of 646781338 is 833187646.

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, 114498 + ... + 120013.

It is an arithmetic number, because the mean of its divisors is an integer number (69650064).

Almost surely, 2^646781338 is an apocalyptic number.

646781338 is a deficient number, since it is larger than the sum of its proper divisors (467619686).

646781338 is a wasteful number, since it uses less digits than its factorization.

646781338 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234717.

The product of its digits is 580608, while the sum is 46.

The square root of 646781338 is about 25431.8960755977. The cubic root of 646781338 is about 864.8069280738.

The spelling of 646781338 in words is "six hundred forty-six million, seven hundred eighty-one thousand, three hundred thirty-eight".