3842821 has 4 divisors (see below), whose sum is σ = 3856972. Its totient is φ = 3828672.

The previous prime is 3842809. The next prime is 3842831. The reversal of 3842821 is 1282483.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1282483 = 59 ⋅21737.

It can be written as a sum of positive squares in 2 ways, for example, as 1185921 + 2656900 = 1089^2 + 1630^2 .

It is a cyclic number.

It is not a de Polignac number, because 3842821 - 2¹⁹ = 3318533 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 3842821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3842801) 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, 6660 + ... + 7213.

It is an arithmetic number, because the mean of its divisors is an integer number (964243).

Almost surely, 2^3842821 is an apocalyptic number.

It is an amenable number.

3842821 is a deficient number, since it is larger than the sum of its proper divisors (14151).

3842821 is a wasteful number, since it uses less digits than its factorization.

3842821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14150.

The product of its digits is 3072, while the sum is 28.

The square root of 3842821 is about 1960.3114548459. The cubic root of 3842821 is about 156.6330429326.

The spelling of 3842821 in words is "three million, eight hundred forty-two thousand, eight hundred twenty-one".