189135781 has 4 divisors (see below), whose sum is σ = 189635200. Its totient is φ = 188636364.

The previous prime is 189135763. The next prime is 189135811. The reversal of 189135781 is 187531981.

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.

It is a cyclic number.

It is not a de Polignac number, because 189135781 - 2⁹ = 189135269 is a prime.

It is a super-2 number, since 2×189135781² = 71544687308959922, 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 (189135181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 249141 + ... + 249898.

It is an arithmetic number, because the mean of its divisors is an integer number (47408800).

Almost surely, 2^189135781 is an apocalyptic number.

It is an amenable number.

189135781 is a deficient number, since it is larger than the sum of its proper divisors (499419).

189135781 is an equidigital number, since it uses as much as digits as its factorization.

189135781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 499418.

The product of its digits is 60480, while the sum is 43.

The square root of 189135781 is about 13752.6645054695. The cubic root of 189135781 is about 574.0167503519.

The spelling of 189135781 in words is "one hundred eighty-nine million, one hundred thirty-five thousand, seven hundred eighty-one".