9918840639 has 4 divisors (see below), whose sum is σ = 13225120856. Its totient is φ = 6612560424.

The previous prime is 9918840593. The next prime is 9918840667. The reversal of 9918840639 is 9360488199.

9918840639 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 9918840639 - 2⁷ = 9918840511 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 (9918840539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1653140104 + ... + 1653140109.

It is an arithmetic number, because the mean of its divisors is an integer number (3306280214).

Almost surely, 2^9918840639 is an apocalyptic number.

9918840639 is a deficient number, since it is larger than the sum of its proper divisors (3306280217).

9918840639 is a wasteful number, since it uses less digits than its factorization.

9918840639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3306280216.

The product of its (nonzero) digits is 3359232, while the sum is 57.

The square root of 9918840639 is about 99593.3764815713. The cubic root of 9918840639 is about 2148.5904327691.

The spelling of 9918840639 in words is "nine billion, nine hundred eighteen million, eight hundred forty thousand, six hundred thirty-nine".