189999989 has 2 divisors, whose sum is σ = 189999990. Its totient is φ = 189999988.

The previous prime is 189999983. The next prime is 190000003. The reversal of 189999989 is 989999981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 189971089 + 28900 = 13783^2 + 170^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-189999989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (189999983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94999994 + 94999995.

It is an arithmetic number, because the mean of its divisors is an integer number (94999995).

Almost surely, 2^189999989 is an apocalyptic number.

It is an amenable number.

189999989 is a deficient number, since it is larger than the sum of its proper divisors (1).

189999989 is an equidigital number, since it uses as much as digits as its factorization.

189999989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34012224, while the sum is 71.

The square root of 189999989 is about 13784.0483530783. The cubic root of 189999989 is about 574.8896968001.

The spelling of 189999989 in words is "one hundred eighty-nine million, nine hundred ninety-nine thousand, nine hundred eighty-nine".