990121212 has 96 divisors (see below), whose sum is σ = 2604571200. Its totient is φ = 325253376.

The previous prime is 990121211. The next prime is 990121247. The reversal of 990121212 is 212121099.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (990121211) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3680614 + ... + 3680882.

It is an arithmetic number, because the mean of its divisors is an integer number (27130950).

Almost surely, 2^990121212 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 990121212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1302285600).

990121212 is an abundant number, since it is smaller than the sum of its proper divisors (1614449988).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

990121212 is a wasteful number, since it uses less digits than its factorization.

990121212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 652 (or 644 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 27.

The square root of 990121212 is about 31466.1915712722. The cubic root of 990121212 is about 996.6961673775.

It can be divided in two parts, 9901 and 21212, that multiplied together give a palindrome (210020012).

The spelling of 990121212 in words is "nine hundred ninety million, one hundred twenty-one thousand, two hundred twelve".