161420905 has 4 divisors (see below), whose sum is σ = 193705092. Its totient is φ = 129136720.

The previous prime is 161420893. The next prime is 161420921. The reversal of 161420905 is 509024161.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 118962649 + 42458256 = 10907^2 + 6516^2 .

It is not a de Polignac number, because 161420905 - 2¹¹ = 161418857 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16142086 + ... + 16142095.

It is an arithmetic number, because the mean of its divisors is an integer number (48426273).

Almost surely, 2^161420905 is an apocalyptic number.

It is an amenable number.

161420905 is a deficient number, since it is larger than the sum of its proper divisors (32284187).

161420905 is an equidigital number, since it uses as much as digits as its factorization.

161420905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32284186.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 161420905 is about 12705.1526948715. The cubic root of 161420905 is about 544.4858434051.

The spelling of 161420905 in words is "one hundred sixty-one million, four hundred twenty thousand, nine hundred five".