189818681 has 4 divisors (see below), whose sum is σ = 204420132. Its totient is φ = 175217232.

The previous prime is 189818633. The next prime is 189818687. The reversal of 189818681 is 186818981.

It is a happy number.

189818681 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 an emirpimes, since its reverse is a distinct semiprime: 186818981 = 67 ⋅2788343.

It can be written as a sum of positive squares in 2 ways, for example, as 43771456 + 146047225 = 6616^2 + 12085^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-189818681 is a prime.

It is a super-2 number, since 2×189818681² = 72062263313159522, which contains 22 as substring.

189818681 is a strobogrammatic number because it is the same when read upside-down.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (189818687) 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, 7300706 + ... + 7300731.

It is an arithmetic number, because the mean of its divisors is an integer number (51105033).

Almost surely, 2^189818681 is an apocalyptic number.

It is an amenable number.

189818681 is a deficient number, since it is larger than the sum of its proper divisors (14601451).

189818681 is a wasteful number, since it uses less digits than its factorization.

189818681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14601450.

The product of its digits is 221184, while the sum is 50.

The square root of 189818681 is about 13777.4700507749. The cubic root of 189818681 is about 574.7067752574.

The spelling of 189818681 in words is "one hundred eighty-nine million, eight hundred eighteen thousand, six hundred eighty-one".