189490987 has 6 divisors (see below), whose sum is σ = 220428348. Its totient is φ = 162420804.

The previous prime is 189490969. The next prime is 189490999. The reversal of 189490987 is 789094981.

It is a de Polignac number, because none of the positive numbers 2^k-189490987 is a prime.

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

It is not an unprimeable number, because it can be changed into a prime (189490787) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1933533 + ... + 1933630.

It is an arithmetic number, because the mean of its divisors is an integer number (36738058).

Almost surely, 2^189490987 is an apocalyptic number.

189490987 is a deficient number, since it is larger than the sum of its proper divisors (30937361).

189490987 is an equidigital number, since it uses as much as digits as its factorization.

189490987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3867177 (or 3867170 counting only the distinct ones).

The product of its (nonzero) digits is 1306368, while the sum is 55.

The square root of 189490987 is about 13765.5725271418. The cubic root of 189490987 is about 574.3758692254.

The spelling of 189490987 in words is "one hundred eighty-nine million, four hundred ninety thousand, nine hundred eighty-seven".