189906081 has 4 divisors (see below), whose sum is σ = 253208112. Its totient is φ = 126604052.

The previous prime is 189906071. The next prime is 189906161. The reversal of 189906081 is 180609981.

189906081 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 180609981 = 3 ⋅60203327.

It is a cyclic number.

It is not a de Polignac number, because 189906081 - 2⁷ = 189905953 is a prime.

It is a super-2 number, since 2×189906081² = 72128639201557122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (189906001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31651011 + ... + 31651016.

It is an arithmetic number, because the mean of its divisors is an integer number (63302028).

Almost surely, 2^189906081 is an apocalyptic number.

It is an amenable number.

189906081 is a deficient number, since it is larger than the sum of its proper divisors (63302031).

189906081 is an equidigital number, since it uses as much as digits as its factorization.

189906081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63302030.

The product of its (nonzero) digits is 31104, while the sum is 42.

The square root of 189906081 is about 13780.6415307851. The cubic root of 189906081 is about 574.7949676044.

It can be divided in two parts, 18 and 9906081, that added together give a palindrome (9906099).

The spelling of 189906081 in words is "one hundred eighty-nine million, nine hundred six thousand, eighty-one".