3688816221 has 10 divisors (see below), whose sum is σ = 5510453982. Its totient is φ = 2459210760.

The previous prime is 3688816163. The next prime is 3688816267. The reversal of 3688816221 is 1226188863.

It can be written as a sum of positive squares in only one way, i.e., 2357588025 + 1331228196 = 48555^2 + 36486^2 .

It is not a de Polignac number, because 3688816221 - 2⁷ = 3688816093 is a prime.

It is a super-2 number, since 2×3688816221² = 27214730224625441682, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3688866221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 22770390 + ... + 22770551.

Almost surely, 2^3688816221 is an apocalyptic number.

It is an amenable number.

3688816221 is a deficient number, since it is larger than the sum of its proper divisors (1821637761).

3688816221 is an equidigital number, since it uses as much as digits as its factorization.

3688816221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45540953 (or 45540944 counting only the distinct ones).

The product of its digits is 221184, while the sum is 45.

The square root of 3688816221 is about 60735.6256327372. The cubic root of 3688816221 is about 1545.1204468262.

The spelling of 3688816221 in words is "three billion, six hundred eighty-eight million, eight hundred sixteen thousand, two hundred twenty-one".