188398421 has 2 divisors, whose sum is σ = 188398422. Its totient is φ = 188398420.

The previous prime is 188398409. The next prime is 188398453. The reversal of 188398421 is 124893881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 139594225 + 48804196 = 11815^2 + 6986^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-188398421 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (188398481) 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, 94199210 + 94199211.

It is an arithmetic number, because the mean of its divisors is an integer number (94199211).

Almost surely, 2^188398421 is an apocalyptic number.

It is an amenable number.

188398421 is a deficient number, since it is larger than the sum of its proper divisors (1).

188398421 is an equidigital number, since it uses as much as digits as its factorization.

188398421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 110592, while the sum is 44.

The square root of 188398421 is about 13725.8304302508. The cubic root of 188398421 is about 573.2698297777.

The spelling of 188398421 in words is "one hundred eighty-eight million, three hundred ninety-eight thousand, four hundred twenty-one".