2001021990 has 32 divisors (see below), whose sum is σ = 5239040256. Its totient is φ = 485096160.

The previous prime is 2001021989. The next prime is 2001022061. The reversal of 2001021990 is 991201002.

It is a self number, because there is not a number n which added to its sum of digits gives 2001021990.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3031522 + ... + 3032181.

It is an arithmetic number, because the mean of its divisors is an integer number (163720008).

Almost surely, 2^2001021990 is an apocalyptic number.

2001021990 is an abundant number, since it is smaller than the sum of its proper divisors (3238018266).

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

2001021990 is a wasteful number, since it uses less digits than its factorization.

2001021990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6063724.

The product of its (nonzero) digits is 324, while the sum is 24.

The square root of 2001021990 is about 44732.7842862480. The cubic root of 2001021990 is about 1260.1356178036.

Adding to 2001021990 its reverse (991201002), we get a palindrome (2992222992).

The spelling of 2001021990 in words is "two billion, one million, twenty-one thousand, nine hundred ninety".