388172321 has 2 divisors, whose sum is σ = 388172322. Its totient is φ = 388172320.

The previous prime is 388172303. The next prime is 388172329. The reversal of 388172321 is 123271883.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 251539600 + 136632721 = 15860^2 + 11689^2 .

It is a cyclic number.

It is not a de Polignac number, because 388172321 - 2²² = 383978017 is a prime.

It is not a weakly prime, because it can be changed into another prime (388172329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 194086160 + 194086161.

It is an arithmetic number, because the mean of its divisors is an integer number (194086161).

Almost surely, 2^388172321 is an apocalyptic number.

It is an amenable number.

388172321 is a deficient number, since it is larger than the sum of its proper divisors (1).

388172321 is an equidigital number, since it uses as much as digits as its factorization.

388172321 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 388172321 is about 19702.0892546958. The cubic root of 388172321 is about 729.4712634680.

The spelling of 388172321 in words is "three hundred eighty-eight million, one hundred seventy-two thousand, three hundred twenty-one".