189305681 has 2 divisors, whose sum is σ = 189305682. Its totient is φ = 189305680.

The previous prime is 189305671. The next prime is 189305719. The reversal of 189305681 is 186503981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 187827025 + 1478656 = 13705^2 + 1216^2 .

It is a cyclic number.

It is not a de Polignac number, because 189305681 - 2¹⁸ = 189043537 is a prime.

It is a super-2 number, since 2×189305681² = 71673281717747522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (189305621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94652840 + 94652841.

It is an arithmetic number, because the mean of its divisors is an integer number (94652841).

Almost surely, 2^189305681 is an apocalyptic number.

It is an amenable number.

189305681 is a deficient number, since it is larger than the sum of its proper divisors (1).

189305681 is an equidigital number, since it uses as much as digits as its factorization.

189305681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 51840, while the sum is 41.

The square root of 189305681 is about 13758.8401037297. The cubic root of 189305681 is about 574.1885779805.

The spelling of 189305681 in words is "one hundred eighty-nine million, three hundred five thousand, six hundred eighty-one".