64651220 has 24 divisors (see below), whose sum is σ = 136533600. Its totient is φ = 25714592.

The previous prime is 64651207. The next prime is 64651241. The reversal of 64651220 is 2215646.

It is a self number, because there is not a number n which added to its sum of digits gives 64651220.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5450 + ... + 12609.

It is an arithmetic number, because the mean of its divisors is an integer number (5688900).

Almost surely, 2^64651220 is an apocalyptic number.

It is an amenable number.

64651220 is an abundant number, since it is smaller than the sum of its proper divisors (71882380).

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

64651220 is a wasteful number, since it uses less digits than its factorization.

64651220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18247 (or 18245 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 26.

The square root of 64651220 is about 8040.5982364498. The cubic root of 64651220 is about 401.3521325273.

Adding to 64651220 its reverse (2215646), we get a palindrome (66866866).

The spelling of 64651220 in words is "sixty-four million, six hundred fifty-one thousand, two hundred twenty".