189989981 has 8 divisors (see below), whose sum is σ = 191040960. Its totient is φ = 188942688.

The previous prime is 189989903. The next prime is 189989983.

189989981 is nontrivially palindromic in base 10.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 189989981 - 2²² = 185795677 is a prime.

It is a super-2 number, since 2×189989981² = 72192385760760722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (189989983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 200150 + ... + 201096.

It is an arithmetic number, because the mean of its divisors is an integer number (23880120).

Almost surely, 2^189989981 is an apocalyptic number.

It is an amenable number.

189989981 is a deficient number, since it is larger than the sum of its proper divisors (1050979).

189989981 is an equidigital number, since it uses as much as digits as its factorization.

189989981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1843.

The product of its digits is 3359232, while the sum is 62.

The square root of 189989981 is about 13783.6853199716. The cubic root of 189989981 is about 574.8796027695.

The spelling of 189989981 in words is "one hundred eighty-nine million, nine hundred eighty-nine thousand, nine hundred eighty-one".