189898561 has 2 divisors, whose sum is σ = 189898562. Its totient is φ = 189898560.

The previous prime is 189898531. The next prime is 189898589. The reversal of 189898561 is 165898981.

189898561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 103408561 + 86490000 = 10169^2 + 9300^2 .

It is a cyclic number.

It is not a de Polignac number, because 189898561 - 2⁷ = 189898433 is a prime.

It is a super-2 number, since 2×189898561² = 72122926939741442, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is not a weakly prime, because it can be changed into another prime (189898531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94949280 + 94949281.

It is an arithmetic number, because the mean of its divisors is an integer number (94949281).

Almost surely, 2^189898561 is an apocalyptic number.

It is an amenable number.

189898561 is a deficient number, since it is larger than the sum of its proper divisors (1).

189898561 is an equidigital number, since it uses as much as digits as its factorization.

189898561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1244160, while the sum is 55.

The square root of 189898561 is about 13780.3686815702. The cubic root of 189898561 is about 574.7873804940.

The spelling of 189898561 in words is "one hundred eighty-nine million, eight hundred ninety-eight thousand, five hundred sixty-one".