64477728 has 144 divisors (see below), whose sum is σ = 218907360. Its totient is φ = 18410112.

The previous prime is 64477703. The next prime is 64477729. The reversal of 64477728 is 82777446.

It is a tau number, because it is divible by the number of its divisors (144).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (64477729) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 41575 + ... + 43097.

It is an arithmetic number, because the mean of its divisors is an integer number (1520190).

Almost surely, 2^64477728 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 64477728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109453680).

64477728 is an abundant number, since it is smaller than the sum of its proper divisors (154429632).

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

64477728 is a wasteful number, since it uses less digits than its factorization.

64477728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1556 (or 1535 counting only the distinct ones).

The product of its digits is 526848, while the sum is 45.

The square root of 64477728 is about 8029.8024882310. The cubic root of 64477728 is about 400.9928004959.

The spelling of 64477728 in words is "sixty-four million, four hundred seventy-seven thousand, seven hundred twenty-eight".