161066809 has 4 divisors (see below), whose sum is σ = 165420004. Its totient is φ = 156713616.

The previous prime is 161066803. The next prime is 161066827. The reversal of 161066809 is 908660161.

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 82301184 + 78765625 = 9072^2 + 8875^2 .

It is a cyclic number.

It is not a de Polignac number, because 161066809 - 2¹⁷ = 160935737 is a prime.

It is a super-2 number, since 2×161066809² = 51885033922884962, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (37), and also a Moran number because the ratio is a prime number: 4353157 = 161066809 / (1 + 6 + 1 + 0 + 6 + 6 + 8 + 0 + 9).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161066803) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2176542 + ... + 2176615.

It is an arithmetic number, because the mean of its divisors is an integer number (41355001).

Almost surely, 2^161066809 is an apocalyptic number.

It is an amenable number.

161066809 is a deficient number, since it is larger than the sum of its proper divisors (4353195).

161066809 is an equidigital number, since it uses as much as digits as its factorization.

161066809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4353194.

The product of its (nonzero) digits is 15552, while the sum is 37.

The square root of 161066809 is about 12691.2099108005. The cubic root of 161066809 is about 544.0874203961.

The spelling of 161066809 in words is "one hundred sixty-one million, sixty-six thousand, eight hundred nine".