1001211220989 has 18 divisors (see below), whose sum is σ = 1682307290430. Its totient is φ = 572120697456.

The previous prime is 1001211220987. The next prime is 1001211221033. The reversal of 1001211220989 is 9890221121001.

It can be written as a sum of positive squares in only one way, i.e., 543254495364 + 457956725625 = 737058^2 + 676725^2 .

It is not a de Polignac number, because 1001211220989 - 2¹ = 1001211220987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001211220987) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1135159674 + ... + 1135160555.

It is an arithmetic number, because the mean of its divisors is an integer number (93461516135).

Almost surely, 2^{1001211220989} is an apocalyptic number.

It is an amenable number.

1001211220989 is a deficient number, since it is larger than the sum of its proper divisors (681096069441).

1001211220989 is a wasteful number, since it uses less digits than its factorization.

1001211220989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2270320249 (or 2270320239 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 36.

The spelling of 1001211220989 in words is "one trillion, one billion, two hundred eleven million, two hundred twenty thousand, nine hundred eighty-nine".