9909999421 has 8 divisors (see below), whose sum is σ = 11326319424. Its totient is φ = 8493830880.

The previous prime is 9909999391. The next prime is 9909999439. The reversal of 9909999421 is 1249999099.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 9909999421 - 2⁷ = 9909999293 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 9909999421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9909999221) 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, 214446 + ... + 256528.

It is an arithmetic number, because the mean of its divisors is an integer number (1415789928).

Almost surely, 2^9909999421 is an apocalyptic number.

It is an amenable number.

9909999421 is a deficient number, since it is larger than the sum of its proper divisors (1416320003).

9909999421 is a wasteful number, since it uses less digits than its factorization.

9909999421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75731.

The product of its (nonzero) digits is 4251528, while the sum is 61.

The square root of 9909999421 is about 99548.9800098424. The cubic root of 9909999421 is about 2147.9518566825.

The spelling of 9909999421 in words is "nine billion, nine hundred nine million, nine hundred ninety-nine thousand, four hundred twenty-one".