9921040816 has 40 divisors (see below), whose sum is σ = 19391758848. Its totient is φ = 4916808000.

The previous prime is 9921040813. The next prime is 9921040847. The reversal of 9921040816 is 6180401299.

It is not an unprimeable number, because it can be changed into a prime (9921040813) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2158681 + ... + 2163271.

Almost surely, 2^9921040816 is an apocalyptic number.

It is an amenable number.

9921040816 is a deficient number, since it is larger than the sum of its proper divisors (9470718032).

9921040816 is a wasteful number, since it uses less digits than its factorization.

9921040816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5761 (or 5755 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 40.

The square root of 9921040816 is about 99604.4216689199. The cubic root of 9921040816 is about 2148.7492863400.

The spelling of 9921040816 in words is "nine billion, nine hundred twenty-one million, forty thousand, eight hundred sixteen".