65809664 has 18 divisors (see below), whose sum is σ = 131362770. Its totient is φ = 32904704.

The previous prime is 65809663. The next prime is 65809691. The reversal of 65809664 is 46690856.

It can be written as a sum of positive squares in only one way, i.e., 33547264 + 32262400 = 5792^2 + 5680^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65809661) 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, 128279 + ... + 128790.

Almost surely, 2^65809664 is an apocalyptic number.

65809664 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

65809664 is a deficient number, since it is larger than the sum of its proper divisors (65553106).

65809664 is an equidigital number, since it uses as much as digits as its factorization.

65809664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 257085 (or 257071 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 44.

The square root of 65809664 is about 8112.3155757157. The cubic root of 65809664 is about 403.7351464724.

The spelling of 65809664 in words is "sixty-five million, eight hundred nine thousand, six hundred sixty-four".