638936390 has 16 divisors (see below), whose sum is σ = 1153049040. Its totient is φ = 254916000.

The previous prime is 638936341. The next prime is 638936393. The reversal of 638936390 is 93639836.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638936393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 78236 + ... + 86015.

It is an arithmetic number, because the mean of its divisors is an integer number (72065565).

Almost surely, 2^638936390 is an apocalyptic number.

638936390 is a deficient number, since it is larger than the sum of its proper divisors (514112650).

638936390 is a wasteful number, since it uses less digits than its factorization.

638936390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164647.

The product of its (nonzero) digits is 629856, while the sum is 47.

The square root of 638936390 is about 25277.1911018610. The cubic root of 638936390 is about 861.2962200025.

The spelling of 638936390 in words is "six hundred thirty-eight million, nine hundred thirty-six thousand, three hundred ninety".