640109306899 has 4 divisors (see below), whose sum is σ = 673799270440. Its totient is φ = 606419343360.

The previous prime is 640109306891. The next prime is 640109306957. The reversal of 640109306899 is 998603901046.

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 640109306899 - 2³ = 640109306891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640109306891) 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, 16844981742 + ... + 16844981779.

It is an arithmetic number, because the mean of its divisors is an integer number (168449817610).

Almost surely, 2^640109306899 is an apocalyptic number.

640109306899 is a deficient number, since it is larger than the sum of its proper divisors (33689963541).

640109306899 is a wasteful number, since it uses less digits than its factorization.

640109306899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33689963540.

The product of its (nonzero) digits is 2519424, while the sum is 55.

The spelling of 640109306899 in words is "six hundred forty billion, one hundred nine million, three hundred six thousand, eight hundred ninety-nine".