3902806821 has 32 divisors (see below), whose sum is σ = 5379356160. Its totient is φ = 2515636224.

The previous prime is 3902806793. The next prime is 3902806829. The reversal of 3902806821 is 1286082093.

It is a happy number.

It is not a de Polignac number, because 3902806821 - 2⁷ = 3902806693 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 3902806821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3902806829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4707435 + ... + 4708263.

It is an arithmetic number, because the mean of its divisors is an integer number (168104880).

Almost surely, 2^3902806821 is an apocalyptic number.

It is an amenable number.

3902806821 is a deficient number, since it is larger than the sum of its proper divisors (1476549339).

3902806821 is a wasteful number, since it uses less digits than its factorization.

3902806821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1245.

The product of its (nonzero) digits is 41472, while the sum is 39.

The square root of 3902806821 is about 62472.4484953167. The cubic root of 3902806821 is about 1574.4384420809.

The spelling of 3902806821 in words is "three billion, nine hundred two million, eight hundred six thousand, eight hundred twenty-one".