189434728081 has 9 divisors (see below), whose sum is σ = 190172707921. Its totient is φ = 188699606032.

The previous prime is 189434728027. The next prime is 189434728163. The reversal of 189434728081 is 180827434981.

The square root of 189434728081 is 435241.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 3225217681 + 186209510400 = 56791^2 + 431520^2 .

It is not a de Polignac number, because 189434728081 - 2¹⁹ = 189434203793 is a prime.

It is a super-2 number, since 2×189434728081² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (189434728381) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 137970711 + ... + 137972083.

Almost surely, 2^189434728081 is an apocalyptic number.

189434728081 is the 435241-st square number.

189434728081 is the 217621-st centered octagonal number.

It is an amenable number.

189434728081 is a deficient number, since it is larger than the sum of its proper divisors (737979840).

189434728081 is an frugal number, since it uses more digits than its factorization.

189434728081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3380 (or 1690 counting only the distinct ones).

The product of its (nonzero) digits is 3096576, while the sum is 55.

The spelling of 189434728081 in words is "one hundred eighty-nine billion, four hundred thirty-four million, seven hundred twenty-eight thousand, eighty-one".