990443721 has 8 divisors (see below), whose sum is σ = 1322769664. Its totient is φ = 659206800.

The previous prime is 990443711. The next prime is 990443747. The reversal of 990443721 is 127344099.

990443721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 990443721 - 2⁵ = 990443689 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 990443721.

It is not an unprimeable number, because it can be changed into a prime (990443711) 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, 270130 + ... + 273771.

It is an arithmetic number, because the mean of its divisors is an integer number (165346208).

Almost surely, 2^990443721 is an apocalyptic number.

It is an amenable number.

990443721 is a deficient number, since it is larger than the sum of its proper divisors (332325943).

990443721 is a wasteful number, since it uses less digits than its factorization.

990443721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 544511.

The product of its (nonzero) digits is 54432, while the sum is 39.

The square root of 990443721 is about 31471.3158447498. The cubic root of 990443721 is about 996.8043725096.

The spelling of 990443721 in words is "nine hundred ninety million, four hundred forty-three thousand, seven hundred twenty-one".