65609999 has 16 divisors (see below), whose sum is σ = 81668160. Its totient is φ = 51321600.

The previous prime is 65609989. The next prime is 65610001. The reversal of 65609999 is 99990656.

65609999 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Cunningham number, because it is equal to 90⁴-1.

It is a cyclic number.

It is not a de Polignac number, because 65609999 - 2⁸ = 65609743 is a prime.

65609999 is a modest number, since divided by 9999 gives 6560 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 65609999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65609969) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 4049 + ... + 12149.

It is an arithmetic number, because the mean of its divisors is an integer number (5104260).

Almost surely, 2^65609999 is an apocalyptic number.

65609999 is a deficient number, since it is larger than the sum of its proper divisors (16058161).

65609999 is a wasteful number, since it uses less digits than its factorization.

65609999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8210.

The product of its (nonzero) digits is 1180980, while the sum is 53.

The square root of 65609999 is about 8099.9999382716. Note that the first 4 decimals coincide. The cubic root of 65609999 is about 403.3264251410.

The spelling of 65609999 in words is "sixty-five million, six hundred nine thousand, nine hundred ninety-nine".