3821856221 has 2 divisors, whose sum is σ = 3821856222. Its totient is φ = 3821856220.

The previous prime is 3821856167. The next prime is 3821856239. The reversal of 3821856221 is 1226581283.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3783972196 + 37884025 = 61514^2 + 6155^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3821856221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3821858221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1910928110 + 1910928111.

It is an arithmetic number, because the mean of its divisors is an integer number (1910928111).

Almost surely, 2^3821856221 is an apocalyptic number.

It is an amenable number.

3821856221 is a deficient number, since it is larger than the sum of its proper divisors (1).

3821856221 is an equidigital number, since it uses as much as digits as its factorization.

3821856221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 46080, while the sum is 38.

The square root of 3821856221 is about 61821.1632129322. The cubic root of 3821856221 is about 1563.4768252333.

The spelling of 3821856221 in words is "three billion, eight hundred twenty-one million, eight hundred fifty-six thousand, two hundred twenty-one".