3653821 has 2 divisors, whose sum is σ = 3653822. Its totient is φ = 3653820.

The previous prime is 3653809. The next prime is 3653831. The reversal of 3653821 is 1283563.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2528100 + 1125721 = 1590^2 + 1061^2 .

It is an emirp because it is prime and its reverse (1283563) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3653821 - 2²¹ = 1556669 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 3653821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3653831) 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, 1826910 + 1826911.

It is an arithmetic number, because the mean of its divisors is an integer number (1826911).

Almost surely, 2^3653821 is an apocalyptic number.

It is an amenable number.

3653821 is a deficient number, since it is larger than the sum of its proper divisors (1).

3653821 is an equidigital number, since it uses as much as digits as its factorization.

3653821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4320, while the sum is 28.

The square root of 3653821 is about 1911.4970572826. The cubic root of 3653821 is about 154.0218808511.

It can be divided in two parts, 365 and 3821, that added together give a triangular number (4186 = T₉₁).

The spelling of 3653821 in words is "three million, six hundred fifty-three thousand, eight hundred twenty-one".