161666005 has 16 divisors (see below), whose sum is σ = 205749504. Its totient is φ = 121524480.

The previous prime is 161665997. The next prime is 161666009. The reversal of 161666005 is 500666161.

It is not a de Polignac number, because 161666005 - 2³ = 161665997 is a prime.

It is a super-2 number, since 2×161666005² = 52271794345320050, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161666009) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 68800 + ... + 71110.

It is an arithmetic number, because the mean of its divisors is an integer number (12859344).

Almost surely, 2^161666005 is an apocalyptic number.

It is an amenable number.

161666005 is a deficient number, since it is larger than the sum of its proper divisors (44083499).

161666005 is a wasteful number, since it uses less digits than its factorization.

161666005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3156.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 161666005 is about 12714.7947289762. The cubic root of 161666005 is about 544.7612847888.

The spelling of 161666005 in words is "one hundred sixty-one million, six hundred sixty-six thousand, five".