188138749 has 2 divisors, whose sum is σ = 188138750. Its totient is φ = 188138748.

The previous prime is 188138723. The next prime is 188138771. The reversal of 188138749 is 947831881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 161544100 + 26594649 = 12710^2 + 5157^2 .

It is a cyclic number.

It is not a de Polignac number, because 188138749 - 2¹¹ = 188136701 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 (188138789) 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, 94069374 + 94069375.

It is an arithmetic number, because the mean of its divisors is an integer number (94069375).

Almost surely, 2^188138749 is an apocalyptic number.

It is an amenable number.

188138749 is a deficient number, since it is larger than the sum of its proper divisors (1).

188138749 is an equidigital number, since it uses as much as digits as its factorization.

188138749 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 387072, while the sum is 49.

The square root of 188138749 is about 13716.3679230327. The cubic root of 188138749 is about 573.0063269172.

The spelling of 188138749 in words is "one hundred eighty-eight million, one hundred thirty-eight thousand, seven hundred forty-nine".