161618473 has 4 divisors (see below), whose sum is σ = 171125460. Its totient is φ = 152111488.

The previous prime is 161618461. The next prime is 161618491. The reversal of 161618473 is 374816161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 374816161 = 541 ⋅692821.

It can be written as a sum of positive squares in 2 ways, for example, as 109244304 + 52374169 = 10452^2 + 7237^2 .

It is a cyclic number.

It is not a de Polignac number, because 161618473 - 2⁵ = 161618441 is a prime.

It is a super-2 number, since 2×161618473² = 52241061629703458, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161618173) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4753468 + ... + 4753501.

It is an arithmetic number, because the mean of its divisors is an integer number (42781365).

Almost surely, 2^161618473 is an apocalyptic number.

It is an amenable number.

161618473 is a deficient number, since it is larger than the sum of its proper divisors (9506987).

161618473 is an equidigital number, since it uses as much as digits as its factorization.

161618473 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9506986.

The product of its digits is 24192, while the sum is 37.

The square root of 161618473 is about 12712.9254304428. The cubic root of 161618473 is about 544.7078904847.

The spelling of 161618473 in words is "one hundred sixty-one million, six hundred eighteen thousand, four hundred seventy-three".