161666475 has 24 divisors (see below), whose sum is σ = 267778992. Its totient is φ = 86064000.

The previous prime is 161666473. The next prime is 161666509. The reversal of 161666475 is 574666161.

It is a happy number.

It is not a de Polignac number, because 161666475 - 2¹ = 161666473 is a prime.

It is a super-2 number, since 2×161666475² = 52272098277851250, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161666473) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 47325 + ... + 50625.

It is an arithmetic number, because the mean of its divisors is an integer number (11157458).

Almost surely, 2^161666475 is an apocalyptic number.

161666475 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

161666475 is a deficient number, since it is larger than the sum of its proper divisors (106112517).

161666475 is a wasteful number, since it uses less digits than its factorization.

161666475 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3967 (or 3962 counting only the distinct ones).

The product of its digits is 181440, while the sum is 42.

The square root of 161666475 is about 12714.8132113689. The cubic root of 161666475 is about 544.7618127035.

The spelling of 161666475 in words is "one hundred sixty-one million, six hundred sixty-six thousand, four hundred seventy-five".