89711981 has 2 divisors, whose sum is σ = 89711982. Its totient is φ = 89711980.

The previous prime is 89711959. The next prime is 89712017. The reversal of 89711981 is 18911798.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 60918025 + 28793956 = 7805^2 + 5366^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-89711981 is a prime.

It is a super-2 number, since 2×89711981² = 16096479069888722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (89711381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 44855990 + 44855991.

It is an arithmetic number, because the mean of its divisors is an integer number (44855991).

Almost surely, 2^89711981 is an apocalyptic number.

It is an amenable number.

89711981 is a deficient number, since it is larger than the sum of its proper divisors (1).

89711981 is an equidigital number, since it uses as much as digits as its factorization.

89711981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 44.

The square root of 89711981 is about 9471.6408821281. The cubic root of 89711981 is about 447.6619157535.

The spelling of 89711981 in words is "eighty-nine million, seven hundred eleven thousand, nine hundred eighty-one".