64581220 has 48 divisors (see below), whose sum is σ = 148534848. Its totient is φ = 23391360.

The previous prime is 64581203. The next prime is 64581229. The reversal of 64581220 is 2218546.

It is not an unprimeable number, because it can be changed into a prime (64581229) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 81667 + ... + 82453.

It is an arithmetic number, because the mean of its divisors is an integer number (3094476).

Almost surely, 2^64581220 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 64581220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (74267424).

64581220 is an abundant number, since it is smaller than the sum of its proper divisors (83953628).

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

64581220 is a wasteful number, since it uses less digits than its factorization.

64581220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1180 (or 1178 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 64581220 is about 8036.2441476103. The cubic root of 64581220 is about 401.2072278369.

Adding to 64581220 its reverse (2218546), we get a palindrome (66799766).

The spelling of 64581220 in words is "sixty-four million, five hundred eighty-one thousand, two hundred twenty".