64640916 has 72 divisors (see below), whose sum is σ = 171959424. Its totient is φ = 21228480.

The previous prime is 64640861. The next prime is 64640923. The reversal of 64640916 is 61904646.

64640916 is a `hidden beast` number, since 6 + 4 + 640 + 9 + 1 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a zygodrome in base 3.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 70501 + ... + 71411.

Almost surely, 2^64640916 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 64640916, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85979712).

64640916 is an abundant number, since it is smaller than the sum of its proper divisors (107318508).

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

64640916 is a wasteful number, since it uses less digits than its factorization.

64640916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1003 (or 989 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 64640916 is about 8039.9574625740. The cubic root of 64640916 is about 401.3308091241.

It can be divided in two parts, 64640 and 916, that added together give a palindrome (65556).

The spelling of 64640916 in words is "sixty-four million, six hundred forty thousand, nine hundred sixteen".