161289905 has 8 divisors (see below), whose sum is σ = 221197632. Its totient is φ = 110598768.

The previous prime is 161289899. The next prime is 161289911. The reversal of 161289905 is 509982161.

It is a happy number.

161289905 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (161289899) and next prime (161289911).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 161289905 - 2⁴ = 161289889 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2304107 + ... + 2304176.

It is an arithmetic number, because the mean of its divisors is an integer number (27649704).

Almost surely, 2^161289905 is an apocalyptic number.

It is an amenable number.

161289905 is a deficient number, since it is larger than the sum of its proper divisors (59907727).

161289905 is an equidigital number, since it uses as much as digits as its factorization.

161289905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4608295.

The product of its (nonzero) digits is 38880, while the sum is 41.

The square root of 161289905 is about 12699.9962598420. The cubic root of 161289905 is about 544.3385123240.

The spelling of 161289905 in words is "one hundred sixty-one million, two hundred eighty-nine thousand, nine hundred five".