2001121998 has 16 divisors (see below), whose sum is σ = 4070079360. Its totient is φ = 655734776.

The previous prime is 2001121987. The next prime is 2001121999. The reversal of 2001121998 is 8991211002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001121999) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2826090 + ... + 2826797.

It is an arithmetic number, because the mean of its divisors is an integer number (254379960).

Almost surely, 2^2001121998 is an apocalyptic number.

2001121998 is an abundant number, since it is smaller than the sum of its proper divisors (2068957362).

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

2001121998 is a wasteful number, since it uses less digits than its factorization.

2001121998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5652951.

The product of its (nonzero) digits is 2592, while the sum is 33.

The square root of 2001121998 is about 44733.9021101446. The cubic root of 2001121998 is about 1260.1566106669.

The spelling of 2001121998 in words is "two billion, one million, one hundred twenty-one thousand, nine hundred ninety-eight".