65681664 has 36 divisors (see below), whose sum is σ = 174811056. Its totient is φ = 21893632.

The previous prime is 65681657. The next prime is 65681669. The reversal of 65681664 is 46618656.

It is a super-3 number, since 3×65681664³ (a number of 24 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (65681669) 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 in 3 ways as a sum of consecutive naturals, for example, 41994 + ... + 43529.

Almost surely, 2^65681664 is an apocalyptic number.

65681664 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

65681664 is an abundant number, since it is smaller than the sum of its proper divisors (109129392).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

65681664 is an equidigital number, since it uses as much as digits as its factorization.

65681664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85542 (or 85528 counting only the distinct ones).

The product of its digits is 207360, while the sum is 42.

The square root of 65681664 is about 8104.4224963905. The cubic root of 65681664 is about 403.4732212143.

The spelling of 65681664 in words is "sixty-five million, six hundred eighty-one thousand, six hundred sixty-four".