1001211989 has 2 divisors, whose sum is σ = 1001211990. Its totient is φ = 1001211988.

The previous prime is 1001211961. The next prime is 1001212013. The reversal of 1001211989 is 9891121001.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 872729764 + 128482225 = 29542^2 + 11335^2 .

It is a cyclic number.

It is not a de Polignac number, because 1001211989 - 2²⁰ = 1000163413 is a prime.

It is a super-2 number, since 2×1001211989² = 2004850893834672242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1001211949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 500605994 + 500605995.

It is an arithmetic number, because the mean of its divisors is an integer number (500605995).

Almost surely, 2^1001211989 is an apocalyptic number.

It is an amenable number.

1001211989 is a deficient number, since it is larger than the sum of its proper divisors (1).

1001211989 is an equidigital number, since it uses as much as digits as its factorization.

1001211989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1296, while the sum is 32.

The square root of 1001211989 is about 31641.9340274895. The cubic root of 1001211989 is about 1000.4038332301.

The spelling of 1001211989 in words is "one billion, one million, two hundred eleven thousand, nine hundred eighty-nine".