161862809 has 2 divisors, whose sum is σ = 161862810. Its totient is φ = 161862808.

The previous prime is 161862803. The next prime is 161862823. The reversal of 161862809 is 908268161.

161862809 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 131171209 + 30691600 = 11453^2 + 5540^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161862809 is a prime.

It is not a weakly prime, because it can be changed into another prime (161862803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80931404 + 80931405.

It is an arithmetic number, because the mean of its divisors is an integer number (80931405).

Almost surely, 2^161862809 is an apocalyptic number.

It is an amenable number.

161862809 is a deficient number, since it is larger than the sum of its proper divisors (1).

161862809 is an equidigital number, since it uses as much as digits as its factorization.

161862809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 41472, while the sum is 41.

The square root of 161862809 is about 12722.5315483987. The cubic root of 161862809 is about 544.9822500742.

The spelling of 161862809 in words is "one hundred sixty-one million, eight hundred sixty-two thousand, eight hundred nine".