2001021989 has 2 divisors, whose sum is σ = 2001021990. Its totient is φ = 2001021988.

The previous prime is 2001021983. The next prime is 2001022061. The reversal of 2001021989 is 9891201002.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1456032964 + 544989025 = 38158^2 + 23345^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2001021989 is a prime.

It is a super-2 number, since 2×2001021989² = 8008178000923032242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2001021983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1000510994 + 1000510995.

It is an arithmetic number, because the mean of its divisors is an integer number (1000510995).

Almost surely, 2^2001021989 is an apocalyptic number.

It is an amenable number.

2001021989 is a deficient number, since it is larger than the sum of its proper divisors (1).

2001021989 is an equidigital number, since it uses as much as digits as its factorization.

2001021989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 2001021989 is about 44732.7842750706. The cubic root of 2001021989 is about 1260.1356175937.

The spelling of 2001021989 in words is "two billion, one million, twenty-one thousand, nine hundred eighty-nine".