6640342399 has 4 divisors (see below), whose sum is σ = 6643751400. Its totient is φ = 6636933400.

The previous prime is 6640342391. The next prime is 6640342517. The reversal of 6640342399 is 9932430466.

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 6640342399 - 2³ = 6640342391 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6640342391) 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, 1701577 + ... + 1705474.

It is an arithmetic number, because the mean of its divisors is an integer number (1660937850).

Almost surely, 2^6640342399 is an apocalyptic number.

6640342399 is a deficient number, since it is larger than the sum of its proper divisors (3409001).

6640342399 is a wasteful number, since it uses less digits than its factorization.

6640342399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3409000.

The product of its (nonzero) digits is 839808, while the sum is 46.

The square root of 6640342399 is about 81488.2960860024. The cubic root of 6640342399 is about 1879.5915816249.

The spelling of 6640342399 in words is "six billion, six hundred forty million, three hundred forty-two thousand, three hundred ninety-nine".