3771221681 has 2 divisors, whose sum is σ = 3771221682. Its totient is φ = 3771221680.

The previous prime is 3771221677. The next prime is 3771221717. The reversal of 3771221681 is 1861221773.

3771221681 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2320830625 + 1450391056 = 48175^2 + 38084^2 .

It is a cyclic number.

It is not a de Polignac number, because 3771221681 - 2² = 3771221677 is a prime.

It is a super-2 number, since 2×3771221681² = 28444225934488931522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (3771221621) 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 as a sum of consecutive naturals, namely, 1885610840 + 1885610841.

It is an arithmetic number, because the mean of its divisors is an integer number (1885610841).

Almost surely, 2^3771221681 is an apocalyptic number.

It is an amenable number.

3771221681 is a deficient number, since it is larger than the sum of its proper divisors (1).

3771221681 is an equidigital number, since it uses as much as digits as its factorization.

3771221681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 28224, while the sum is 38.

The square root of 3771221681 is about 61410.2734157730. The cubic root of 3771221681 is about 1556.5414395536.

The spelling of 3771221681 in words is "three billion, seven hundred seventy-one million, two hundred twenty-one thousand, six hundred eighty-one".