6128821 has 2 divisors, whose sum is σ = 6128822. Its totient is φ = 6128820.

The previous prime is 6128819. The next prime is 6128851. The reversal of 6128821 is 1288216.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3276100 + 2852721 = 1810^2 + 1689^2 .

It is a cyclic number.

It is not a de Polignac number, because 6128821 - 2¹ = 6128819 is a prime.

Together with 6128819, it forms a pair of twin primes.

6128821 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 6128821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6128851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3064410 + 3064411.

It is an arithmetic number, because the mean of its divisors is an integer number (3064411).

Almost surely, 2^6128821 is an apocalyptic number.

It is an amenable number.

6128821 is a deficient number, since it is larger than the sum of its proper divisors (1).

6128821 is an equidigital number, since it uses as much as digits as its factorization.

6128821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1536, while the sum is 28.

The square root of 6128821 is about 2475.6455723710. The cubic root of 6128821 is about 183.0033244143.

It can be divided in two parts, 61 and 28821, that added together give a palindrome (28882).

The spelling of 6128821 in words is "six million, one hundred twenty-eight thousand, eight hundred twenty-one".