189936405 has 12 divisors (see below), whose sum is σ = 329223180. Its totient is φ = 101299392.

The previous prime is 189936403. The next prime is 189936419. The reversal of 189936405 is 504639981.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 39162564 + 150773841 = 6258^2 + 12279^2 .

It is not a de Polignac number, because 189936405 - 2¹ = 189936403 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 4220809 = 189936405 / (1 + 8 + 9 + 9 + 3 + 6 + 4 + 0 + 5).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (189936401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2110360 + ... + 2110449.

It is an arithmetic number, because the mean of its divisors is an integer number (27435265).

Almost surely, 2^189936405 is an apocalyptic number.

189936405 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

189936405 is a deficient number, since it is larger than the sum of its proper divisors (139286775).

189936405 is a wasteful number, since it uses less digits than its factorization.

189936405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4220820 (or 4220817 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 45.

The square root of 189936405 is about 13781.7417259213. The cubic root of 189936405 is about 574.8255601914.

The spelling of 189936405 in words is "one hundred eighty-nine million, nine hundred thirty-six thousand, four hundred five".