664140321 has 24 divisors (see below), whose sum is σ = 1034744256. Its totient is φ = 408054240.

The previous prime is 664140317. The next prime is 664140331. The reversal of 664140321 is 123041466.

It is not a de Polignac number, because 664140321 - 2² = 664140317 is a prime.

It is not an unprimeable number, because it can be changed into a prime (664140331) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 75756 + ... + 84066.

It is an arithmetic number, because the mean of its divisors is an integer number (43114344).

Almost surely, 2^664140321 is an apocalyptic number.

It is an amenable number.

664140321 is a deficient number, since it is larger than the sum of its proper divisors (370603935).

664140321 is a wasteful number, since it uses less digits than its factorization.

664140321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9013 (or 9010 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 664140321 is about 25770.9200650656. The cubic root of 664140321 is about 872.4755847937.

Adding to 664140321 its reverse (123041466), we get a palindrome (787181787).

The spelling of 664140321 in words is "six hundred sixty-four million, one hundred forty thousand, three hundred twenty-one".