189928991 has 16 divisors (see below), whose sum is σ = 221722944. Its totient is φ = 159335424.

The previous prime is 189928969. The next prime is 189928993. The reversal of 189928991 is 199829981.

189928991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 189928991 - 2¹⁴ = 189912607 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (189928993) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 68651 + ... + 71363.

It is an arithmetic number, because the mean of its divisors is an integer number (13857684).

Almost surely, 2^189928991 is an apocalyptic number.

189928991 is a deficient number, since it is larger than the sum of its proper divisors (31793953).

189928991 is a wasteful number, since it uses less digits than its factorization.

189928991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2930.

The product of its digits is 839808, while the sum is 56.

The square root of 189928991 is about 13781.4727442317. The cubic root of 189928991 is about 574.8180808246.

The spelling of 189928991 in words is "one hundred eighty-nine million, nine hundred twenty-eight thousand, nine hundred ninety-one".