990230821 has 4 divisors (see below), whose sum is σ = 1001357100. Its totient is φ = 979104544.

The previous prime is 990230819. The next prime is 990230833. The reversal of 990230821 is 128032099.

990230821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 543542596 + 446688225 = 23314^2 + 21135^2 .

It is a cyclic number.

It is not a de Polignac number, because 990230821 - 2¹ = 990230819 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 (990230321) 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, 5563006 + ... + 5563183.

It is an arithmetic number, because the mean of its divisors is an integer number (250339275).

Almost surely, 2^990230821 is an apocalyptic number.

It is an amenable number.

990230821 is a deficient number, since it is larger than the sum of its proper divisors (11126279).

990230821 is a wasteful number, since it uses less digits than its factorization.

990230821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11126278.

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 990230821 is about 31467.9332178013. The cubic root of 990230821 is about 996.7329449753.

The spelling of 990230821 in words is "nine hundred ninety million, two hundred thirty thousand, eight hundred twenty-one".