388133821 has 2 divisors, whose sum is σ = 388133822. Its totient is φ = 388133820.

The previous prime is 388133819. The next prime is 388133827. The reversal of 388133821 is 128331883.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 387105625 + 1028196 = 19675^2 + 1014^2 .

It is a cyclic number.

It is not a de Polignac number, because 388133821 - 2¹ = 388133819 is a prime.

Together with 388133819, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (388133827) 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, 194066910 + 194066911.

It is an arithmetic number, because the mean of its divisors is an integer number (194066911).

Almost surely, 2^388133821 is an apocalyptic number.

It is an amenable number.

388133821 is a deficient number, since it is larger than the sum of its proper divisors (1).

388133821 is an equidigital number, since it uses as much as digits as its factorization.

388133821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27648, while the sum is 37.

The square root of 388133821 is about 19701.1121767275. The cubic root of 388133821 is about 729.4471456809.

The spelling of 388133821 in words is "three hundred eighty-eight million, one hundred thirty-three thousand, eight hundred twenty-one".