64781664 has 48 divisors (see below), whose sum is σ = 170956800. Its totient is φ = 21479040.

The previous prime is 64781653. The next prime is 64781669. The reversal of 64781664 is 46618746.

It is a tau number, because it is divible by the number of its divisors (48).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64781669) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17409 + ... + 20799.

It is an arithmetic number, because the mean of its divisors is an integer number (3561600).

Almost surely, 2^64781664 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 64781664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85478400).

64781664 is an abundant number, since it is smaller than the sum of its proper divisors (106175136).

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

64781664 is a wasteful number, since it uses less digits than its factorization.

64781664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3603 (or 3595 counting only the distinct ones).

The product of its digits is 193536, while the sum is 42.

The square root of 64781664 is about 8048.7057344644. The cubic root of 64781664 is about 401.6218815292.

The spelling of 64781664 in words is "sixty-four million, seven hundred eighty-one thousand, six hundred sixty-four".