65408640 has 256 divisors, whose sum is σ = 240883200. Its totient is φ = 14929920.

The previous prime is 65408627. The next prime is 65408641. The reversal of 65408640 is 4680456.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (65408641) 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 31 ways as a sum of consecutive naturals, for example, 401199 + ... + 401361.

It is an arithmetic number, because the mean of its divisors is an integer number (940950).

Almost surely, 2^65408640 is an apocalyptic number.

65408640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 65408640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120441600).

65408640 is an abundant number, since it is smaller than the sum of its proper divisors (175474560).

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

65408640 is a wasteful number, since it uses less digits than its factorization.

65408640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215 (or 203 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 33.

The square root of 65408640 is about 8087.5608189367. The cubic root of 65408640 is about 402.9133954660.

The spelling of 65408640 in words is "sixty-five million, four hundred eight thousand, six hundred forty".