647687021438 has 32 divisors (see below), whose sum is σ = 1061747719200. Its totient is φ = 295150310784.

The previous prime is 647687021393. The next prime is 647687021447. The reversal of 647687021438 is 834120786746.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 755645 + ... + 1366152.

It is an arithmetic number, because the mean of its divisors is an integer number (33179616225).

Almost surely, 2^647687021438 is an apocalyptic number.

647687021438 is a deficient number, since it is larger than the sum of its proper divisors (414060697762).

647687021438 is a wasteful number, since it uses less digits than its factorization.

647687021438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2122124.

The product of its (nonzero) digits is 10838016, while the sum is 56.

The spelling of 647687021438 in words is "six hundred forty-seven billion, six hundred eighty-seven million, twenty-one thousand, four hundred thirty-eight".