638405471505 has 16 divisors (see below), whose sum is σ = 1021808867904. Its totient is φ = 340362880320.

The previous prime is 638405471477. The next prime is 638405471569. The reversal of 638405471505 is 505174504836.

638405471505 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 638405471505 - 2⁶ = 638405471441 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7458391 + ... + 7543500.

It is an arithmetic number, because the mean of its divisors is an integer number (63863054244).

Almost surely, 2^638405471505 is an apocalyptic number.

It is an amenable number.

638405471505 is a deficient number, since it is larger than the sum of its proper divisors (383403396399).

638405471505 is a wasteful number, since it uses less digits than its factorization.

638405471505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15004736.

The product of its (nonzero) digits is 2016000, while the sum is 48.

The spelling of 638405471505 in words is "six hundred thirty-eight billion, four hundred five million, four hundred seventy-one thousand, five hundred five".