3939821 has 8 divisors (see below), whose sum is σ = 4281600. Its totient is φ = 3611520.

The previous prime is 3939811. The next prime is 3939829. The reversal of 3939821 is 1289393.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-3939821 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 (3939829) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2756 + ... + 3933.

It is an arithmetic number, because the mean of its divisors is an integer number (535200).

Almost surely, 2^3939821 is an apocalyptic number.

3939821 is a gapful number since it is divisible by the number (31) formed by its first and last digit.

It is an amenable number.

3939821 is a deficient number, since it is larger than the sum of its proper divisors (341779).

3939821 is a wasteful number, since it uses less digits than its factorization.

3939821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6739.

The product of its digits is 11664, while the sum is 35.

The square root of 3939821 is about 1984.8982341672. The cubic root of 3939821 is about 157.9400108748.

The spelling of 3939821 in words is "three million, nine hundred thirty-nine thousand, eight hundred twenty-one".