638407405655 has 8 divisors (see below), whose sum is σ = 766500552384. Its totient is φ = 510451480800.

The previous prime is 638407405633. The next prime is 638407405663. The reversal of 638407405655 is 556504704836.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 638407405655 - 2¹² = 638407401559 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 638407405597 and 638407405606.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34295231 + ... + 34313840.

It is an arithmetic number, because the mean of its divisors is an integer number (95812569048).

Almost surely, 2^638407405655 is an apocalyptic number.

638407405655 is a deficient number, since it is larger than the sum of its proper divisors (128093146729).

638407405655 is a wasteful number, since it uses less digits than its factorization.

638407405655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68610937.

The product of its (nonzero) digits is 12096000, while the sum is 53.

The spelling of 638407405655 in words is "six hundred thirty-eight billion, four hundred seven million, four hundred five thousand, six hundred fifty-five".