3851821 has 4 divisors (see below), whose sum is σ = 3906144. Its totient is φ = 3797500.

The previous prime is 3851819. The next prime is 3851839. The reversal of 3851821 is 1281583.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1281583 = 23 ⋅55721.

It is a cyclic number.

It is not a de Polignac number, because 3851821 - 2¹ = 3851819 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 3851821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3851801) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27055 + ... + 27196.

It is an arithmetic number, because the mean of its divisors is an integer number (976536).

Almost surely, 2^3851821 is an apocalyptic number.

It is an amenable number.

3851821 is a deficient number, since it is larger than the sum of its proper divisors (54323).

3851821 is an equidigital number, since it uses as much as digits as its factorization.

3851821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54322.

The product of its digits is 1920, while the sum is 28.

The square root of 3851821 is about 1962.6056659451. The cubic root of 3851821 is about 156.7552273295.

The spelling of 3851821 in words is "three million, eight hundred fifty-one thousand, eight hundred twenty-one".