189219923721 has 20 divisors (see below), whose sum is σ = 283373904132. Its totient is φ = 125828844768.

The previous prime is 189219923713. The next prime is 189219923747. The reversal of 189219923721 is 127329912981.

189219923721 is a `hidden beast` number, since 1 + 89 + 2 + 199 + 2 + 372 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 87254661321 + 101965262400 = 295389^2 + 319320^2 .

It is not a de Polignac number, because 189219923721 - 2³ = 189219923713 is a prime.

It is not an unprimeable number, because it can be changed into a prime (189219923791) 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 19 ways as a sum of consecutive naturals, for example, 2909970 + ... + 2974283.

Almost surely, 2^189219923721 is an apocalyptic number.

It is an amenable number.

189219923721 is a deficient number, since it is larger than the sum of its proper divisors (94153980411).

189219923721 is an equidigital number, since it uses as much as digits as its factorization.

189219923721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5884662 (or 5884653 counting only the distinct ones).

The product of its digits is 979776, while the sum is 54.

The spelling of 189219923721 in words is "one hundred eighty-nine billion, two hundred nineteen million, nine hundred twenty-three thousand, seven hundred twenty-one".