189808681 has 2 divisors, whose sum is σ = 189808682. Its totient is φ = 189808680.

The previous prime is 189808649. The next prime is 189808747. The reversal of 189808681 is 186808981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 126765081 + 63043600 = 11259^2 + 7940^2 .

It is a cyclic number.

It is not a de Polignac number, because 189808681 - 2⁵ = 189808649 is a prime.

It is a super-2 number, since 2×189808681² = 72054670765919522, which contains 22 as substring.

189808681 is a strobogrammatic number because it is the same when read upside-down.

It is not a weakly prime, because it can be changed into another prime (189808601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94904340 + 94904341.

It is an arithmetic number, because the mean of its divisors is an integer number (94904341).

Almost surely, 2^189808681 is an apocalyptic number.

It is an amenable number.

189808681 is a deficient number, since it is larger than the sum of its proper divisors (1).

189808681 is an equidigital number, since it uses as much as digits as its factorization.

189808681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 221184, while the sum is 49.

The square root of 189808681 is about 13777.1071346636. The cubic root of 189808681 is about 574.6966828741.

The spelling of 189808681 in words is "one hundred eighty-nine million, eight hundred eight thousand, six hundred eighty-one".