388638431 has 2 divisors, whose sum is σ = 388638432. Its totient is φ = 388638430.

The previous prime is 388638421. The next prime is 388638457. The reversal of 388638431 is 134836883.

It is a weak prime.

It is an emirp because it is prime and its reverse (134836883) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-388638431 is a prime.

It is a super-2 number, since 2×388638431² = 302079660100283522, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (388638401) 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 as a sum of consecutive naturals, namely, 194319215 + 194319216.

It is an arithmetic number, because the mean of its divisors is an integer number (194319216).

Almost surely, 2^388638431 is an apocalyptic number.

388638431 is a deficient number, since it is larger than the sum of its proper divisors (1).

388638431 is an equidigital number, since it uses as much as digits as its factorization.

388638431 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 331776, while the sum is 44.

The square root of 388638431 is about 19713.9146543755. The cubic root of 388638431 is about 729.7631251223.

The spelling of 388638431 in words is "three hundred eighty-eight million, six hundred thirty-eight thousand, four hundred thirty-one".