620821 has 2 divisors, whose sum is σ = 620822. Its totient is φ = 620820.

The previous prime is 620813. The next prime is 620827. The reversal of 620821 is 128026.

It is a happy number.

620821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 617796 + 3025 = 786^2 + 55^2 .

It is a cyclic number.

It is not a de Polignac number, because 620821 - 2³ = 620813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (620827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310410 + 310411.

It is an arithmetic number, because the mean of its divisors is an integer number (310411).

2⁶²⁰⁸²¹ is an apocalyptic number.

It is an amenable number.

620821 is a deficient number, since it is larger than the sum of its proper divisors (1).

620821 is an equidigital number, since it uses as much as digits as its factorization.

620821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 620821 is about 787.9219504494. The cubic root of 620821 is about 85.3078113101.

Adding to 620821 its reverse (128026), we get a palindrome (748847).

It can be divided in two parts, 620 and 821, that added together give a palindrome (1441).

The spelling of 620821 in words is "six hundred twenty thousand, eight hundred twenty-one".