189209987 has 2 divisors, whose sum is σ = 189209988. Its totient is φ = 189209986.

The previous prime is 189209953. The next prime is 189210041. The reversal of 189209987 is 789902981.

189209987 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 189209987 - 2²⁰ = 188161411 is a prime.

It is not a weakly prime, because it can be changed into another prime (189209387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94604993 + 94604994.

It is an arithmetic number, because the mean of its divisors is an integer number (94604994).

Almost surely, 2^189209987 is an apocalyptic number.

189209987 is a deficient number, since it is larger than the sum of its proper divisors (1).

189209987 is an equidigital number, since it uses as much as digits as its factorization.

189209987 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 653184, while the sum is 53.

The square root of 189209987 is about 13755.3621180978. The cubic root of 189209987 is about 574.0918109200.

The spelling of 189209987 in words is "one hundred eighty-nine million, two hundred nine thousand, nine hundred eighty-seven".