189991291 has 8 divisors (see below), whose sum is σ = 217361664. Its totient is φ = 162678120.

The previous prime is 189991289. The next prime is 189991301. The reversal of 189991291 is 192199981.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 189991291 - 2¹ = 189991289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (189991231) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6925 + ... + 20686.

It is an arithmetic number, because the mean of its divisors is an integer number (27170208).

Almost surely, 2^189991291 is an apocalyptic number.

189991291 is a deficient number, since it is larger than the sum of its proper divisors (27370373).

189991291 is an equidigital number, since it uses as much as digits as its factorization.

189991291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28601.

The product of its digits is 104976, while the sum is 49.

The square root of 189991291 is about 13783.7328398370. The cubic root of 189991291 is about 574.8809240507.

The spelling of 189991291 in words is "one hundred eighty-nine million, nine hundred ninety-one thousand, two hundred ninety-one".