489821821 has 4 divisors (see below), whose sum is σ = 494671644. Its totient is φ = 484972000.

The previous prime is 489821809. The next prime is 489821837. The reversal of 489821821 is 128128984.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 256160025 + 233661796 = 16005^2 + 15286^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-489821821 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (489821851) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2424760 + ... + 2424961.

It is an arithmetic number, because the mean of its divisors is an integer number (123667911).

Almost surely, 2^489821821 is an apocalyptic number.

It is an amenable number.

489821821 is a deficient number, since it is larger than the sum of its proper divisors (4849823).

489821821 is a wasteful number, since it uses less digits than its factorization.

489821821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4849822.

The product of its digits is 73728, while the sum is 43.

The square root of 489821821 is about 22131.9186018745. The cubic root of 489821821 is about 788.2779458107.

The spelling of 489821821 in words is "four hundred eighty-nine million, eight hundred twenty-one thousand, eight hundred twenty-one".