188406473681 has 2 divisors, whose sum is σ = 188406473682. Its totient is φ = 188406473680.

The previous prime is 188406473663. The next prime is 188406473693. The reversal of 188406473681 is 186374604881.

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., 126906937600 + 61499536081 = 356240^2 + 247991^2 .

It is an emirp because it is prime and its reverse (186374604881) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 188406473681 - 2¹⁴ = 188406457297 is a prime.

It is a super-2 number, since 2×188406473681² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (188406473881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94203236840 + 94203236841.

It is an arithmetic number, because the mean of its divisors is an integer number (94203236841).

Almost surely, 2^188406473681 is an apocalyptic number.

It is an amenable number.

188406473681 is a deficient number, since it is larger than the sum of its proper divisors (1).

188406473681 is an equidigital number, since it uses as much as digits as its factorization.

188406473681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6193152, while the sum is 56.

The spelling of 188406473681 in words is "one hundred eighty-eight billion, four hundred six million, four hundred seventy-three thousand, six hundred eighty-one".