990121243 has 8 divisors (see below), whose sum is σ = 1006617600. Its totient is φ = 973675560.

The previous prime is 990121211. The next prime is 990121247. The reversal of 990121243 is 342121099.

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 990121243 - 2⁵ = 990121211 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (990121247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27798 + ... + 52468.

It is an arithmetic number, because the mean of its divisors is an integer number (125827200).

Almost surely, 2^990121243 is an apocalyptic number.

990121243 is a deficient number, since it is larger than the sum of its proper divisors (16496357).

990121243 is a wasteful number, since it uses less digits than its factorization.

990121243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25337.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 990121243 is about 31466.1920638644. The cubic root of 990121243 is about 996.6961777794.

The spelling of 990121243 in words is "nine hundred ninety million, one hundred twenty-one thousand, two hundred forty-three".