3992821 has 4 divisors (see below), whose sum is σ = 4563232. Its totient is φ = 3422412.

The previous prime is 3992797. The next prime is 3992837. The reversal of 3992821 is 1282993.

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.

It is not a de Polignac number, because 3992821 - 2⁹ = 3992309 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 (3992221) 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, 285195 + ... + 285208.

It is an arithmetic number, because the mean of its divisors is an integer number (1140808).

Almost surely, 2^3992821 is an apocalyptic number.

It is an amenable number.

3992821 is a deficient number, since it is larger than the sum of its proper divisors (570411).

3992821 is an equidigital number, since it uses as much as digits as its factorization.

3992821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 570410.

The product of its digits is 7776, while the sum is 34.

The square root of 3992821 is about 1998.2044439947. The cubic root of 3992821 is about 158.6450820586.

The spelling of 3992821 in words is "three million, nine hundred ninety-two thousand, eight hundred twenty-one".