189361681 has 2 divisors, whose sum is σ = 189361682. Its totient is φ = 189361680.

The previous prime is 189361559. The next prime is 189361687. The reversal of 189361681 is 186163981.

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., 165508225 + 23853456 = 12865^2 + 4884^2 .

It is an emirp because it is prime and its reverse (186163981) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 189361681 - 2¹⁵ = 189328913 is a prime.

It is a super-2 number, since 2×189361681² = 71715692462291522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (189361687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94680840 + 94680841.

It is an arithmetic number, because the mean of its divisors is an integer number (94680841).

Almost surely, 2^189361681 is an apocalyptic number.

It is an amenable number.

189361681 is a deficient number, since it is larger than the sum of its proper divisors (1).

189361681 is an equidigital number, since it uses as much as digits as its factorization.

189361681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 62208, while the sum is 43.

The square root of 189361681 is about 13760.8750085160. The cubic root of 189361681 is about 574.2451908092.

The spelling of 189361681 in words is "one hundred eighty-nine million, three hundred sixty-one thousand, six hundred eighty-one".