64806640 has 40 divisors (see below), whose sum is σ = 157231008. Its totient is φ = 24794880.

The previous prime is 64806631. The next prime is 64806641. The reversal of 64806640 is 4660846.

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 64806596 and 64806605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64806641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15771 + ... + 19450.

Almost surely, 2^64806640 is an apocalyptic number.

It is an amenable number.

64806640 is an abundant number, since it is smaller than the sum of its proper divisors (92424368).

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

64806640 is a wasteful number, since it uses less digits than its factorization.

64806640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35257 (or 35251 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 34.

The square root of 64806640 is about 8050.2571387503. The cubic root of 64806640 is about 401.6734888239.

The spelling of 64806640 in words is "sixty-four million, eight hundred six thousand, six hundred forty".