2181998106 has 96 divisors (see below), whose sum is σ = 5128643520. Its totient is φ = 668908800.

The previous prime is 2181998101. The next prime is 2181998107. The reversal of 2181998106 is 6018991812.

It is a super-2 number, since 2×2181998106² = 9522231469175174472, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (2181998101) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 919101 + ... + 921471.

It is an arithmetic number, because the mean of its divisors is an integer number (53423370).

Almost surely, 2^2181998106 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2181998106, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2564321760).

2181998106 is an abundant number, since it is smaller than the sum of its proper divisors (2946645414).

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

2181998106 is a wasteful number, since it uses less digits than its factorization.

2181998106 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2492 (or 2489 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 45.

The square root of 2181998106 is about 46711.8625832882. The cubic root of 2181998106 is about 1297.0342859550.

The spelling of 2181998106 in words is "two billion, one hundred eighty-one million, nine hundred ninety-eight thousand, one hundred six".