9921990418 has 12 divisors (see below), whose sum is σ = 15707528910. Its totient is φ = 4699889856.

The previous prime is 9921990391. The next prime is 9921990431. The reversal of 9921990418 is 8140991299.

9921990418 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 9548612089 + 373378329 = 97717^2 + 19323^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6870463 + ... + 6871906.

Almost surely, 2^9921990418 is an apocalyptic number.

9921990418 is a deficient number, since it is larger than the sum of its proper divisors (5785538492).

9921990418 is a wasteful number, since it uses less digits than its factorization.

9921990418 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13742409 (or 13742390 counting only the distinct ones).

The product of its (nonzero) digits is 419904, while the sum is 52.

The square root of 9921990418 is about 99609.1884215508. The cubic root of 9921990418 is about 2148.8178406903.

The spelling of 9921990418 in words is "nine billion, nine hundred twenty-one million, nine hundred ninety thousand, four hundred eighteen".