889979821 has 2 divisors, whose sum is σ = 889979822. Its totient is φ = 889979820.

The previous prime is 889979819. The next prime is 889979851. The reversal of 889979821 is 128979988.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 553660900 + 336318921 = 23530^2 + 18339^2 .

It is a cyclic number.

It is not a de Polignac number, because 889979821 - 2¹ = 889979819 is a prime.

Together with 889979819, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 889979821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (889979851) 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, 444989910 + 444989911.

It is an arithmetic number, because the mean of its divisors is an integer number (444989911).

Almost surely, 2^889979821 is an apocalyptic number.

It is an amenable number.

889979821 is a deficient number, since it is larger than the sum of its proper divisors (1).

889979821 is an equidigital number, since it uses as much as digits as its factorization.

889979821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5225472, while the sum is 61.

The square root of 889979821 is about 29832.5295776272. The cubic root of 889979821 is about 961.8929018211.

The spelling of 889979821 in words is "eight hundred eighty-nine million, nine hundred seventy-nine thousand, eight hundred twenty-one".