64641616 has 80 divisors (see below), whose sum is σ = 145021968. Its totient is φ = 27648000.

The previous prime is 64641611. The next prime is 64641617. The reversal of 64641616 is 61614646.

64641616 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 577600 + 64064016 = 760^2 + 8004^2 .

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64641611) by changing a digit.

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, 357046 + ... + 357226.

Almost surely, 2^64641616 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 64641616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (72510984).

64641616 is an abundant number, since it is smaller than the sum of its proper divisors (80380352).

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

64641616 is a wasteful number, since it uses less digits than its factorization.

64641616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320 (or 314 counting only the distinct ones).

The product of its digits is 20736, while the sum is 34.

The square root of 64641616 is about 8040.0009950248. Note that the first 3 decimals coincide. The cubic root of 64641616 is about 401.3322577966.

It can be divided in two parts, 646416 and 16, that multiplied together give a square (10342656 = 3216²).

The spelling of 64641616 in words is "sixty-four million, six hundred forty-one thousand, six hundred sixteen".