3557821 has 2 divisors, whose sum is σ = 3557822. Its totient is φ = 3557820.

The previous prime is 3557803. The next prime is 3557831. The reversal of 3557821 is 1287553.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2292196 + 1265625 = 1514^2 + 1125^2 .

It is an emirp because it is prime and its reverse (1287553) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3557821 - 2¹⁹ = 3033533 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3557831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1778910 + 1778911.

It is an arithmetic number, because the mean of its divisors is an integer number (1778911).

Almost surely, 2^3557821 is an apocalyptic number.

It is an amenable number.

3557821 is a deficient number, since it is larger than the sum of its proper divisors (1).

3557821 is an equidigital number, since it uses as much as digits as its factorization.

3557821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8400, while the sum is 31.

The square root of 3557821 is about 1886.2187041804. The cubic root of 3557821 is about 152.6609748730.

The spelling of 3557821 in words is "three million, five hundred fifty-seven thousand, eight hundred twenty-one".