188706671981 has 2 divisors, whose sum is σ = 188706671982. Its totient is φ = 188706671980.

The previous prime is 188706671927. The next prime is 188706672001. The reversal of 188706671981 is 189176607881.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 145397316100 + 43309355881 = 381310^2 + 208109^2 .

It is a cyclic number.

It is not a de Polignac number, because 188706671981 - 2⁶ = 188706671917 is a prime.

It is a super-2 number, since 2×188706671981² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (188706671911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94353335990 + 94353335991.

It is an arithmetic number, because the mean of its divisors is an integer number (94353335991).

Almost surely, 2^188706671981 is an apocalyptic number.

It is an amenable number.

188706671981 is a deficient number, since it is larger than the sum of its proper divisors (1).

188706671981 is an equidigital number, since it uses as much as digits as its factorization.

188706671981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8128512, while the sum is 62.

The spelling of 188706671981 in words is "one hundred eighty-eight billion, seven hundred six million, six hundred seventy-one thousand, nine hundred eighty-one".