64640400 has 240 divisors, whose sum is σ = 232485120. Its totient is φ = 15219200.

The previous prime is 64640399. The next prime is 64640437. The reversal of 64640400 is 404646.

64640400 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (24).

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 47 ways as a sum of consecutive naturals, for example, 778759 + ... + 778841.

It is an arithmetic number, because the mean of its divisors is an integer number (968688).

Almost surely, 2^64640400 is an apocalyptic number.

64640400 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 64640400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116242560).

64640400 is an abundant number, since it is smaller than the sum of its proper divisors (167844720).

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

64640400 is a wasteful number, since it uses less digits than its factorization.

64640400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174 (or 163 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 24.

The square root of 64640400 is about 8039.9253727880. The cubic root of 64640400 is about 401.3297412388.

The spelling of 64640400 in words is "sixty-four million, six hundred forty thousand, four hundred".