638403576865 has 32 divisors (see below), whose sum is σ = 821594234880. Its totient is φ = 475134289344.

The previous prime is 638403576817. The next prime is 638403576929. The reversal of 638403576865 is 568675304836.

It is a cyclic number.

It is not a de Polignac number, because 638403576865 - 2¹⁷ = 638403445793 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 84292 + ... + 1133098.

It is an arithmetic number, because the mean of its divisors is an integer number (25674819840).

Almost surely, 2^638403576865 is an apocalyptic number.

It is an amenable number.

638403576865 is a deficient number, since it is larger than the sum of its proper divisors (183190658015).

638403576865 is a wasteful number, since it uses less digits than its factorization.

638403576865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1048981.

The product of its (nonzero) digits is 87091200, while the sum is 61.

The spelling of 638403576865 in words is "six hundred thirty-eight billion, four hundred three million, five hundred seventy-six thousand, eight hundred sixty-five".