9904428421 has 4 divisors (see below), whose sum is σ = 10223926144. Its totient is φ = 9584930700.

The previous prime is 9904428407. The next prime is 9904428427. The reversal of 9904428421 is 1248244099.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 9904428421 - 2¹⁷ = 9904297349 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 (9904428427) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 159748815 + ... + 159748876.

It is an arithmetic number, because the mean of its divisors is an integer number (2555981536).

Almost surely, 2^9904428421 is an apocalyptic number.

It is an amenable number.

9904428421 is a deficient number, since it is larger than the sum of its proper divisors (319497723).

9904428421 is a wasteful number, since it uses less digits than its factorization.

9904428421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 319497722.

The product of its (nonzero) digits is 165888, while the sum is 43.

The square root of 9904428421 is about 99520.9948754533. The cubic root of 9904428421 is about 2147.5492840789.

The spelling of 9904428421 in words is "nine billion, nine hundred four million, four hundred twenty-eight thousand, four hundred twenty-one".