189545981 has 4 divisors (see below), whose sum is σ = 190283772. Its totient is φ = 188808192.

The previous prime is 189545977. The next prime is 189546011.

189545981 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 187443481 + 2102500 = 13691^2 + 1450^2 .

It is a cyclic number.

It is not a de Polignac number, because 189545981 - 2² = 189545977 is a prime.

It is a super-2 number, since 2×189545981² = 71855357826504722, 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 (189545281) 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, 368510 + ... + 369023.

It is an arithmetic number, because the mean of its divisors is an integer number (47570943).

Almost surely, 2^189545981 is an apocalyptic number.

It is an amenable number.

189545981 is a deficient number, since it is larger than the sum of its proper divisors (737791).

189545981 is an equidigital number, since it uses as much as digits as its factorization.

189545981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 737790.

The product of its digits is 518400, while the sum is 50.

The square root of 189545981 is about 13767.5699017655. The cubic root of 189545981 is about 574.4314288975.

The spelling of 189545981 in words is "one hundred eighty-nine million, five hundred forty-five thousand, nine hundred eighty-one".