9990231221 has 8 divisors (see below), whose sum is σ = 10113347160. Its totient is φ = 9867356928.

The previous prime is 9990231193. The next prime is 9990231241. The reversal of 9990231221 is 1221320999.

It can be written as a sum of positive squares in 4 ways, for example, as 968080996 + 9022150225 = 31114^2 + 94985^2 .

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 9990231221 - 2⁶ = 9990231157 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9990231241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23495 + ... + 143291.

It is an arithmetic number, because the mean of its divisors is an integer number (1264168395).

Almost surely, 2^9990231221 is an apocalyptic number.

It is an amenable number.

9990231221 is a deficient number, since it is larger than the sum of its proper divisors (123115939).

9990231221 is a wasteful number, since it uses less digits than its factorization.

9990231221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120823.

The product of its (nonzero) digits is 17496, while the sum is 38.

The square root of 9990231221 is about 99951.1441705396. The cubic root of 9990231221 is about 2153.7329215897.

The spelling of 9990231221 in words is "nine billion, nine hundred ninety million, two hundred thirty-one thousand, two hundred twenty-one".