165298561 has 2 divisors, whose sum is σ = 165298562. Its totient is φ = 165298560.

The previous prime is 165298513. The next prime is 165298591. The reversal of 165298561 is 165892561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 100801600 + 64496961 = 10040^2 + 8031^2 .

It is an emirp because it is prime and its reverse (165892561) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 165298561 - 2¹⁹ = 164774273 is a prime.

It is a super-2 number, since 2×165298561² = 54647228537341442, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is not a weakly prime, because it can be changed into another prime (165298591) 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 as a sum of consecutive naturals, namely, 82649280 + 82649281.

It is an arithmetic number, because the mean of its divisors is an integer number (82649281).

Almost surely, 2^165298561 is an apocalyptic number.

It is an amenable number.

165298561 is a deficient number, since it is larger than the sum of its proper divisors (1).

165298561 is an equidigital number, since it uses as much as digits as its factorization.

165298561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 129600, while the sum is 43.

The square root of 165298561 is about 12856.8487974309. The cubic root of 165298561 is about 548.8112739558.

The spelling of 165298561 in words is "one hundred sixty-five million, two hundred ninety-eight thousand, five hundred sixty-one".