4086821 has 2 divisors, whose sum is σ = 4086822. Its totient is φ = 4086820.

The previous prime is 4086811. The next prime is 4086829. The reversal of 4086821 is 1286804.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4056196 + 30625 = 2014^2 + 175^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-4086821 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is equal to p₂₈₈₉₀₂ and since 4086821 and 288902 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (4086829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2043410 + 2043411.

It is an arithmetic number, because the mean of its divisors is an integer number (2043411).

Almost surely, 2^4086821 is an apocalyptic number.

It is an amenable number.

4086821 is a deficient number, since it is larger than the sum of its proper divisors (1).

4086821 is an equidigital number, since it uses as much as digits as its factorization.

4086821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3072, while the sum is 29.

The square root of 4086821 is about 2021.5887316663. The cubic root of 4086821 is about 159.8803923807.

The spelling of 4086821 in words is "four million, eighty-six thousand, eight hundred twenty-one".