638654044823 has 4 divisors (see below), whose sum is σ = 638662355760. Its totient is φ = 638645733888.

The previous prime is 638654044799. The next prime is 638654044829. The reversal of 638654044823 is 328440456836.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 638654044823 - 2³⁴ = 621474175639 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638654044829) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 4039115 + ... + 4194252.

It is an arithmetic number, because the mean of its divisors is an integer number (159665588940).

Almost surely, 2^638654044823 is an apocalyptic number.

638654044823 is a deficient number, since it is larger than the sum of its proper divisors (8310937).

638654044823 is an equidigital number, since it uses as much as digits as its factorization.

638654044823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8310936.

The product of its (nonzero) digits is 13271040, while the sum is 53.

The spelling of 638654044823 in words is "six hundred thirty-eight billion, six hundred fifty-four million, forty-four thousand, eight hundred twenty-three".