161838405 has 20 divisors (see below), whose sum is σ = 290111052. Its totient is φ = 86313600.

The previous prime is 161838403. The next prime is 161838431. The reversal of 161838405 is 504838161.

161838405 is a `hidden beast` number, since 1 + 618 + 38 + 4 + 0 + 5 = 666.

161838405 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 81162081 + 80676324 = 9009^2 + 8982^2 .

It is not a de Polignac number, because 161838405 - 2¹ = 161838403 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 161838405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161838403) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 199396 + ... + 200205.

Almost surely, 2^161838405 is an apocalyptic number.

161838405 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

161838405 is a deficient number, since it is larger than the sum of its proper divisors (128272647).

161838405 is an equidigital number, since it uses as much as digits as its factorization.

161838405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 399618 (or 399609 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 161838405 is about 12721.5724263945. The cubic root of 161838405 is about 544.9548597689.

The spelling of 161838405 in words is "one hundred sixty-one million, eight hundred thirty-eight thousand, four hundred five".