189666405 has 18 divisors (see below), whose sum is σ = 328915314. Its totient is φ = 101106144.

The previous prime is 189666391. The next prime is 189666437. The reversal of 189666405 is 504666981.

It can be written as a sum of positive squares in 3 ways, for example, as 20848356 + 168818049 = 4566^2 + 12993^2 .

It is not a de Polignac number, because 189666405 - 2¹³ = 189658213 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

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 17 ways as a sum of consecutive naturals, for example, 91359 + ... + 93411.

It is an arithmetic number, because the mean of its divisors is an integer number (18273073).

Almost surely, 2^189666405 is an apocalyptic number.

189666405 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

189666405 is a deficient number, since it is larger than the sum of its proper divisors (139248909).

189666405 is an frugal number, since it uses more digits than its factorization.

189666405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4117 (or 2061 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 45.

The square root of 189666405 is about 13771.9426734212. The cubic root of 189666405 is about 574.5530540664.

Multiplying 189666405 by its sum of digits (45), we get a square (8534988225 = 92385²).

189666405 divided by its sum of digits (45) gives a square (4214809 = 2053²).

The spelling of 189666405 in words is "one hundred eighty-nine million, six hundred sixty-six thousand, four hundred five".