188705381 has 2 divisors, whose sum is σ = 188705382. Its totient is φ = 188705380.

The previous prime is 188705353. The next prime is 188705399. The reversal of 188705381 is 183507881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 145684900 + 43020481 = 12070^2 + 6559^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-188705381 is a prime.

It is a super-2 number, since 2×188705381² = 71219441636710322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (188705311) 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, 94352690 + 94352691.

It is an arithmetic number, because the mean of its divisors is an integer number (94352691).

Almost surely, 2^188705381 is an apocalyptic number.

It is an amenable number.

188705381 is a deficient number, since it is larger than the sum of its proper divisors (1).

188705381 is an equidigital number, since it uses as much as digits as its factorization.

188705381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 53760, while the sum is 41.

The square root of 188705381 is about 13737.0077163842. The cubic root of 188705381 is about 573.5810061698.

The spelling of 188705381 in words is "one hundred eighty-eight million, seven hundred five thousand, three hundred eighty-one".