9984921638 has 4 divisors (see below), whose sum is σ = 14977382460. Its totient is φ = 4992460818.

The previous prime is 9984921619. The next prime is 9984921673. The reversal of 9984921638 is 8361294899.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8361294899 = 85451 ⋅97849.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2496230408 + ... + 2496230411.

It is an arithmetic number, because the mean of its divisors is an integer number (3744345615).

Almost surely, 2^9984921638 is an apocalyptic number.

9984921638 is a deficient number, since it is larger than the sum of its proper divisors (4992460822).

9984921638 is a wasteful number, since it uses less digits than its factorization.

9984921638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4992460821.

The product of its digits is 6718464, while the sum is 59.

The square root of 9984921638 is about 99924.5797489286. The cubic root of 9984921638 is about 2153.3513004526.

The spelling of 9984921638 in words is "nine billion, nine hundred eighty-four million, nine hundred twenty-one thousand, six hundred thirty-eight".