64640321 has 4 divisors (see below), whose sum is σ = 64978944. Its totient is φ = 64301700.

The previous prime is 64640311. The next prime is 64640339. The reversal of 64640321 is 12304646.

64640321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 64640321 - 2¹⁸ = 64378177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64640311) 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 3 ways as a sum of consecutive naturals, for example, 169025 + ... + 169406.

It is an arithmetic number, because the mean of its divisors is an integer number (16244736).

Almost surely, 2^64640321 is an apocalyptic number.

It is an amenable number.

64640321 is a deficient number, since it is larger than the sum of its proper divisors (338623).

64640321 is a wasteful number, since it uses less digits than its factorization.

64640321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 338622.

The product of its (nonzero) digits is 3456, while the sum is 26.

The square root of 64640321 is about 8039.9204598056. The cubic root of 64640321 is about 401.3295777442.

Adding to 64640321 its reverse (12304646), we get a palindrome (76944967).

The spelling of 64640321 in words is "sixty-four million, six hundred forty thousand, three hundred twenty-one".