646656642 has 32 divisors (see below), whose sum is σ = 1521547200. Its totient is φ = 202872384.

The previous prime is 646656631. The next prime is 646656649. The reversal of 646656642 is 246656646.

646656642 is a `hidden beast` number, since 6 + 46 + 6 + 566 + 42 = 666.

It is not an unprimeable number, because it can be changed into a prime (646656649) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 351292 + ... + 353127.

It is an arithmetic number, because the mean of its divisors is an integer number (47548350).

Almost surely, 2^646656642 is an apocalyptic number.

646656642 is an abundant number, since it is smaller than the sum of its proper divisors (874890558).

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

646656642 is a wasteful number, since it uses less digits than its factorization.

646656642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 704447 (or 704441 counting only the distinct ones).

The product of its digits is 1244160, while the sum is 45.

The square root of 646656642 is about 25429.4443903126. Note that the first 3 decimals coincide. The cubic root of 646656642 is about 864.7513477773.

The spelling of 646656642 in words is "six hundred forty-six million, six hundred fifty-six thousand, six hundred forty-two".