64440231 has 4 divisors (see below), whose sum is σ = 85920312. Its totient is φ = 42960152.

The previous prime is 64440223. The next prime is 64440241. The reversal of 64440231 is 13204446.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 64440231 - 2³ = 64440223 is a prime.

It is a super-2 number, since 2×64440231² = 8305086742666722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64440241) 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 3 ways as a sum of consecutive naturals, for example, 10740036 + ... + 10740041.

It is an arithmetic number, because the mean of its divisors is an integer number (21480078).

Almost surely, 2^64440231 is an apocalyptic number.

64440231 is a deficient number, since it is larger than the sum of its proper divisors (21480081).

64440231 is a wasteful number, since it uses less digits than its factorization.

64440231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21480080.

The product of its (nonzero) digits is 2304, while the sum is 24.

The square root of 64440231 is about 8027.4672842684. The cubic root of 64440231 is about 400.9150530154.

Adding to 64440231 its reverse (13204446), we get a palindrome (77644677).

The spelling of 64440231 in words is "sixty-four million, four hundred forty thousand, two hundred thirty-one".