188813221 has 2 divisors, whose sum is σ = 188813222. Its totient is φ = 188813220.

The previous prime is 188813167. The next prime is 188813231. The reversal of 188813221 is 122318881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 118504996 + 70308225 = 10886^2 + 8385^2 .

It is an emirp because it is prime and its reverse (122318881) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 188813221 - 2¹⁵ = 188780453 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (188813231) 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 as a sum of consecutive naturals, namely, 94406610 + 94406611.

It is an arithmetic number, because the mean of its divisors is an integer number (94406611).

Almost surely, 2^188813221 is an apocalyptic number.

It is an amenable number.

188813221 is a deficient number, since it is larger than the sum of its proper divisors (1).

188813221 is an equidigital number, since it uses as much as digits as its factorization.

188813221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6144, while the sum is 34.

The square root of 188813221 is about 13740.9323191696. The cubic root of 188813221 is about 573.6902473519.

The spelling of 188813221 in words is "one hundred eighty-eight million, eight hundred thirteen thousand, two hundred twenty-one".