638378612787 has 16 divisors (see below), whose sum is σ = 881022758912. Its totient is φ = 410734920960.

The previous prime is 638378612771. The next prime is 638378612827. The reversal of 638378612787 is 787216873836.

It is not a de Polignac number, because 638378612787 - 2⁴ = 638378612771 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638378612687) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9317758 + ... + 9386019.

It is an arithmetic number, because the mean of its divisors is an integer number (55063922432).

Almost surely, 2^638378612787 is an apocalyptic number.

638378612787 is a deficient number, since it is larger than the sum of its proper divisors (242644146125).

638378612787 is a wasteful number, since it uses less digits than its factorization.

638378612787 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18704178.

The product of its digits is 113799168, while the sum is 66.

The spelling of 638378612787 in words is "six hundred thirty-eight billion, three hundred seventy-eight million, six hundred twelve thousand, seven hundred eighty-seven".