168990565 has 4 divisors (see below), whose sum is σ = 202788684. Its totient is φ = 135192448.

The previous prime is 168990527. The next prime is 168990571. The reversal of 168990565 is 565099861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 565099861 = 14327 ⋅39443.

It can be written as a sum of positive squares in 2 ways, for example, as 131951169 + 37039396 = 11487^2 + 6086^2 .

It is a cyclic number.

It is not a de Polignac number, because 168990565 - 2⁹ = 168990053 is a prime.

It is a super-2 number, since 2×168990565² = 57115622118038450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16899052 + ... + 16899061.

It is an arithmetic number, because the mean of its divisors is an integer number (50697171).

Almost surely, 2^168990565 is an apocalyptic number.

It is an amenable number.

168990565 is a deficient number, since it is larger than the sum of its proper divisors (33798119).

168990565 is an equidigital number, since it uses as much as digits as its factorization.

168990565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33798118.

The product of its (nonzero) digits is 583200, while the sum is 49.

The square root of 168990565 is about 12999.6371103197. The cubic root of 168990565 is about 552.8671924209.

The spelling of 168990565 in words is "one hundred sixty-eight million, nine hundred ninety thousand, five hundred sixty-five".