189978071 has 4 divisors (see below), whose sum is σ = 191859144. Its totient is φ = 188097000.

The previous prime is 189978067. The next prime is 189978073. The reversal of 189978071 is 170879981.

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

It is a cyclic number.

It is not a de Polignac number, because 189978071 - 2² = 189978067 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 (189978073) 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 3 ways as a sum of consecutive naturals, for example, 940385 + ... + 940586.

It is an arithmetic number, because the mean of its divisors is an integer number (47964786).

Almost surely, 2^189978071 is an apocalyptic number.

189978071 is a deficient number, since it is larger than the sum of its proper divisors (1881073).

189978071 is a wasteful number, since it uses less digits than its factorization.

189978071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1881072.

The product of its (nonzero) digits is 254016, while the sum is 50.

The square root of 189978071 is about 13783.2532807026. The cubic root of 189978071 is about 574.8675899270.

The spelling of 189978071 in words is "one hundred eighty-nine million, nine hundred seventy-eight thousand, seventy-one".