63664640 has 80 divisors (see below), whose sum is σ = 164473848. Its totient is φ = 23494656.

The previous prime is 63664633. The next prime is 63664651. The reversal of 63664640 is 4646636.

It can be written as a sum of positive squares in 4 ways, for example, as 51609856 + 12054784 = 7184^2 + 3472^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is a self number, because there is not a number n which added to its sum of digits gives 63664640.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32324 + ... + 34236.

Almost surely, 2^63664640 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 63664640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (82236924).

63664640 is an abundant number, since it is smaller than the sum of its proper divisors (100809208).

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

63664640 is a wasteful number, since it uses less digits than its factorization.

63664640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1949 (or 1933 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 35.

The square root of 63664640 is about 7979.0124702246. The cubic root of 63664640 is about 399.3001094306.

The spelling of 63664640 in words is "sixty-three million, six hundred sixty-four thousand, six hundred forty".