638538207 has 16 divisors (see below), whose sum is σ = 914925312. Its totient is φ = 394669440.

The previous prime is 638538181. The next prime is 638538233. The reversal of 638538207 is 702835836.

It is an interprime number because it is at equal distance from previous prime (638538181) and next prime (638538233).

It is not a de Polignac number, because 638538207 - 2²⁶ = 571429343 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638538247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 90019 + ... + 96852.

It is an arithmetic number, because the mean of its divisors is an integer number (57182832).

Almost surely, 2^638538207 is an apocalyptic number.

638538207 is a gapful number since it is divisible by the number (67) formed by its first and last digit.

638538207 is a deficient number, since it is larger than the sum of its proper divisors (276387105).

638538207 is a wasteful number, since it uses less digits than its factorization.

638538207 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186958.

The product of its (nonzero) digits is 241920, while the sum is 42.

The square root of 638538207 is about 25269.3135442972. The cubic root of 638538207 is about 861.1172638574.

The spelling of 638538207 in words is "six hundred thirty-eight million, five hundred thirty-eight thousand, two hundred seven".