911021989 has 2 divisors, whose sum is σ = 911021990. Its totient is φ = 911021988.

The previous prime is 911021987. The next prime is 911021999. The reversal of 911021989 is 989120119.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 490976964 + 420045025 = 22158^2 + 20495^2 .

It is a cyclic number.

It is not a de Polignac number, because 911021989 - 2¹ = 911021987 is a prime.

It is a super-2 number, since 2×911021989² = 1659922128883032242, which contains 22 as substring.

Together with 911021987, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (911021987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 455510994 + 455510995.

It is an arithmetic number, because the mean of its divisors is an integer number (455510995).

Almost surely, 2^911021989 is an apocalyptic number.

It is an amenable number.

911021989 is a deficient number, since it is larger than the sum of its proper divisors (1).

911021989 is an equidigital number, since it uses as much as digits as its factorization.

911021989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11664, while the sum is 40.

The square root of 911021989 is about 30183.1408074110. The cubic root of 911021989 is about 969.4147420723.

The spelling of 911021989 in words is "nine hundred eleven million, twenty-one thousand, nine hundred eighty-nine".