3984821 has 4 divisors (see below), whose sum is σ = 3988992. Its totient is φ = 3980652.

The previous prime is 3984809. The next prime is 3984823. The reversal of 3984821 is 1284893.

It is a happy number.

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 a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1284893 = 89 ⋅14437.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3984821 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3984823) 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, 140 + ... + 2826.

It is an arithmetic number, because the mean of its divisors is an integer number (997248).

Almost surely, 2^3984821 is an apocalyptic number.

It is an amenable number.

3984821 is a deficient number, since it is larger than the sum of its proper divisors (4171).

3984821 is a wasteful number, since it uses less digits than its factorization.

3984821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4170.

The product of its digits is 13824, while the sum is 35.

The square root of 3984821 is about 1996.2016431213. The cubic root of 3984821 is about 158.5390576689.

The spelling of 3984821 in words is "three million, nine hundred eighty-four thousand, eight hundred twenty-one".