1605810161 has 2 divisors, whose sum is σ = 1605810162. Its totient is φ = 1605810160.

The previous prime is 1605810119. The next prime is 1605810163. The reversal of 1605810161 is 1610185061.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1364194225 + 241615936 = 36935^2 + 15544^2 .

It is a cyclic number.

It is not a de Polignac number, because 1605810161 - 2³⁰ = 532068337 is a prime.

Together with 1605810163, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1605810163) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 802905080 + 802905081.

It is an arithmetic number, because the mean of its divisors is an integer number (802905081).

Almost surely, 2^1605810161 is an apocalyptic number.

It is an amenable number.

1605810161 is a deficient number, since it is larger than the sum of its proper divisors (1).

1605810161 is an equidigital number, since it uses as much as digits as its factorization.

1605810161 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1440, while the sum is 29.

The square root of 1605810161 is about 40072.5611984061. The cubic root of 1605810161 is about 1171.0211361899.

The spelling of 1605810161 in words is "one billion, six hundred five million, eight hundred ten thousand, one hundred sixty-one".