64643920 has 40 divisors (see below), whose sum is σ = 163962720. Its totient is φ = 23506560.

The previous prime is 64643903. The next prime is 64643923. The reversal of 64643920 is 2934646.

64643920 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64643923) 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 7 ways as a sum of consecutive naturals, for example, 35850 + ... + 37609.

It is an arithmetic number, because the mean of its divisors is an integer number (4099068).

Almost surely, 2^64643920 is an apocalyptic number.

It is an amenable number.

64643920 is an abundant number, since it is smaller than the sum of its proper divisors (99318800).

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

64643920 is a wasteful number, since it uses less digits than its factorization.

64643920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73483 (or 73477 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 34.

The square root of 64643920 is about 8040.1442773124. The cubic root of 64643920 is about 401.3370259248.

The spelling of 64643920 in words is "sixty-four million, six hundred forty-three thousand, nine hundred twenty".