640132321 has 4 divisors (see below), whose sum is σ = 640242352. Its totient is φ = 640022292.

The previous prime is 640132291. The next prime is 640132349. The reversal of 640132321 is 123231046.

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 640132321 - 2⁵ = 640132289 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 640132292 and 640132301.

It is not an unprimeable number, because it can be changed into a prime (640138321) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45771 + ... + 58096.

It is an arithmetic number, because the mean of its divisors is an integer number (160060588).

Almost surely, 2^640132321 is an apocalyptic number.

It is an amenable number.

640132321 is a deficient number, since it is larger than the sum of its proper divisors (110031).

640132321 is a wasteful number, since it uses less digits than its factorization.

640132321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110030.

The product of its (nonzero) digits is 864, while the sum is 22.

The square root of 640132321 is about 25300.8363695748. The cubic root of 640132321 is about 861.8332629520.

Adding to 640132321 its reverse (123231046), we get a palindrome (763363367).

The spelling of 640132321 in words is "six hundred forty million, one hundred thirty-two thousand, three hundred twenty-one".