609821 has 2 divisors, whose sum is σ = 609822. Its totient is φ = 609820.

The previous prime is 609809. The next prime is 609859. The reversal of 609821 is 128906.

609821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 511225 + 98596 = 715^2 + 314^2 .

It is a cyclic number.

It is not a de Polignac number, because 609821 - 2⁶ = 609757 is a prime.

It is a Sophie Germain prime.

It is a Chen 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 (609221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 304910 + 304911.

It is an arithmetic number, because the mean of its divisors is an integer number (304911).

2⁶⁰⁹⁸²¹ is an apocalyptic number.

It is an amenable number.

609821 is a deficient number, since it is larger than the sum of its proper divisors (1).

609821 is an equidigital number, since it uses as much as digits as its factorization.

609821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 609821 is about 780.9103661753. The cubic root of 609821 is about 84.8009645227.

The spelling of 609821 in words is "six hundred nine thousand, eight hundred twenty-one".