638005291 has 48 divisors (see below), whose sum is σ = 864138240. Its totient is φ = 459360000.

The previous prime is 638005267. The next prime is 638005321. The reversal of 638005291 is 192500836.

It is not a de Polignac number, because 638005291 - 2⁵ = 638005259 is a prime.

638005291 is a modest number, since divided by 5291 gives 638 as remainder.

It is not an unprimeable number, because it can be changed into a prime (638005261) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 849166 + ... + 849916.

It is an arithmetic number, because the mean of its divisors is an integer number (18002880).

Almost surely, 2^638005291 is an apocalyptic number.

638005291 is a deficient number, since it is larger than the sum of its proper divisors (226132949).

638005291 is a wasteful number, since it uses less digits than its factorization.

638005291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 856 (or 845 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 638005291 is about 25258.7666167610. The cubic root of 638005291 is about 860.8776379499.

The spelling of 638005291 in words is "six hundred thirty-eight million, five thousand, two hundred ninety-one".