638581200785 has 24 divisors (see below), whose sum is σ = 842346149568. Its totient is φ = 464393872800.

The previous prime is 638581200743. The next prime is 638581200787. The reversal of 638581200785 is 587002185836.

It is not a de Polignac number, because 638581200785 - 2⁶ = 638581200721 is a prime.

It is not an unprimeable number, because it can be changed into a prime (638581200787) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17300900 + ... + 17337770.

It is an arithmetic number, because the mean of its divisors is an integer number (35097756232).

Almost surely, 2^638581200785 is an apocalyptic number.

It is an amenable number.

638581200785 is a deficient number, since it is larger than the sum of its proper divisors (203764948783).

638581200785 is a wasteful number, since it uses less digits than its factorization.

638581200785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65525 (or 65514 counting only the distinct ones).

The product of its (nonzero) digits is 3225600, while the sum is 53.

The spelling of 638581200785 in words is "six hundred thirty-eight billion, five hundred eighty-one million, two hundred thousand, seven hundred eighty-five".