64817720 has 64 divisors (see below), whose sum is σ = 163023840. Its totient is φ = 22988800.

The previous prime is 64817693. The next prime is 64817741. The reversal of 64817720 is 2771846.

It is a happy number.

64817720 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16244 + ... + 19836.

Almost surely, 2^64817720 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 64817720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (81511920).

64817720 is an abundant number, since it is smaller than the sum of its proper divisors (98206120).

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

64817720 is a wasteful number, since it uses less digits than its factorization.

64817720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3656 (or 3652 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 35.

The square root of 64817720 is about 8050.9452861139. The cubic root of 64817720 is about 401.6963789097.

The spelling of 64817720 in words is "sixty-four million, eight hundred seventeen thousand, seven hundred twenty".