388731221 has 2 divisors, whose sum is σ = 388731222. Its totient is φ = 388731220.

The previous prime is 388731181. The next prime is 388731269. The reversal of 388731221 is 122137883.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 314530225 + 74200996 = 17735^2 + 8614^2 .

It is a cyclic number.

It is not a de Polignac number, because 388731221 - 2¹⁰ = 388730197 is a prime.

It is a super-2 number, since 2×388731221² = 302223924360301682, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (388731121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 194365610 + 194365611.

It is an arithmetic number, because the mean of its divisors is an integer number (194365611).

Almost surely, 2^388731221 is an apocalyptic number.

It is an amenable number.

388731221 is a deficient number, since it is larger than the sum of its proper divisors (1).

388731221 is an equidigital number, since it uses as much as digits as its factorization.

388731221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16128, while the sum is 35.

The square root of 388731221 is about 19716.2679277798. The cubic root of 388731221 is about 729.8211990942.

The spelling of 388731221 in words is "three hundred eighty-eight million, seven hundred thirty-one thousand, two hundred twenty-one".