3930821 has 4 divisors (see below), whose sum is σ = 3948672. Its totient is φ = 3912972.

The previous prime is 3930811. The next prime is 3930827. The reversal of 3930821 is 1280393.

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 a cyclic number.

It is not a de Polignac number, because 3930821 - 2¹⁰ = 3929797 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 (3930827) 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, 8591 + ... + 9036.

It is an arithmetic number, because the mean of its divisors is an integer number (987168).

Almost surely, 2^3930821 is an apocalyptic number.

It is an amenable number.

3930821 is a deficient number, since it is larger than the sum of its proper divisors (17851).

3930821 is a wasteful number, since it uses less digits than its factorization.

3930821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17850.

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 3930821 is about 1982.6298192048. The cubic root of 3930821 is about 157.8196548271.

The spelling of 3930821 in words is "three million, nine hundred thirty thousand, eight hundred twenty-one".