161919405 has 48 divisors (see below), whose sum is σ = 295311744. Its totient is φ = 85095360.

The previous prime is 161919397. The next prime is 161919409. The reversal of 161919405 is 504919161.

161919405 is a `hidden beast` number, since 161 + 91 + 9 + 405 = 666.

It is not a de Polignac number, because 161919405 - 2³ = 161919397 is a prime.

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 161919405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161919409) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 85327 + ... + 87203.

It is an arithmetic number, because the mean of its divisors is an integer number (6152328).

Almost surely, 2^161919405 is an apocalyptic number.

161919405 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

161919405 is a deficient number, since it is larger than the sum of its proper divisors (133392339).

161919405 is an equidigital number, since it uses as much as digits as its factorization.

161919405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1968 (or 1956 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 36.

The square root of 161919405 is about 12724.7555968671. The cubic root of 161919405 is about 545.0457611044.

The spelling of 161919405 in words is "one hundred sixty-one million, nine hundred nineteen thousand, four hundred five".