64366640 has 80 divisors (see below), whose sum is σ = 164052000. Its totient is φ = 23341056.

The previous prime is 64366609. The next prime is 64366667. The reversal of 64366640 is 4666346.

It is a tau number, because it is divible by the number of its divisors (80).

It is a self number, because there is not a number n which added to its sum of digits gives 64366640.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 60836 + ... + 61884.

It is an arithmetic number, because the mean of its divisors is an integer number (2050650).

Almost surely, 2^64366640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 64366640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (82026000).

64366640 is an abundant number, since it is smaller than the sum of its proper divisors (99685360).

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

64366640 is a wasteful number, since it uses less digits than its factorization.

64366640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1134 (or 1128 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 35.

The square root of 64366640 is about 8022.8822750929. The cubic root of 64366640 is about 400.7623793545.

The spelling of 64366640 in words is "sixty-four million, three hundred sixty-six thousand, six hundred forty".