899981 has 2 divisors, whose sum is σ = 899982. Its totient is φ = 899980.

The previous prime is 899971. The next prime is 900001. The reversal of 899981 is 189998.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 477481 + 422500 = 691^2 + 650^2 .

It is a cyclic number.

It is not a de Polignac number, because 899981 - 2⁶ = 899917 is a prime.

It is a super-2 number, since 2×899981² = 1619931600722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (899971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 449990 + 449991.

It is an arithmetic number, because the mean of its divisors is an integer number (449991).

2⁸⁹⁹⁹⁸¹ is an apocalyptic number.

It is an amenable number.

899981 is a deficient number, since it is larger than the sum of its proper divisors (1).

899981 is an equidigital number, since it uses as much as digits as its factorization.

899981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 46656, while the sum is 44.

The square root of 899981 is about 948.6732841184. The cubic root of 899981 is about 96.5482590373.

The spelling of 899981 in words is "eight hundred ninety-nine thousand, nine hundred eighty-one".