989821 has 4 divisors (see below), whose sum is σ = 1131232. Its totient is φ = 848412.

The previous prime is 989803. The next prime is 989827. The reversal of 989821 is 128989.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 128989 = 7 ⋅18427.

It is a cyclic number.

It is not a de Polignac number, because 989821 - 2⁹ = 989309 is a prime.

It is a super-2 number, since 2×989821² = 1959491224082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (989827) 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 in 3 ways as a sum of consecutive naturals, for example, 70695 + ... + 70708.

It is an arithmetic number, because the mean of its divisors is an integer number (282808).

2⁹⁸⁹⁸²¹ is an apocalyptic number.

It is an amenable number.

989821 is a deficient number, since it is larger than the sum of its proper divisors (141411).

989821 is a wasteful number, since it uses less digits than its factorization.

989821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141410.

The product of its digits is 10368, while the sum is 37.

The square root of 989821 is about 994.8974821558. The cubic root of 989821 is about 99.6595422003.

The spelling of 989821 in words is "nine hundred eighty-nine thousand, eight hundred twenty-one".