3981721481 has 2 divisors, whose sum is σ = 3981721482. Its totient is φ = 3981721480.

The previous prime is 3981721477. The next prime is 3981721501. The reversal of 3981721481 is 1841271893.

3981721481 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., 3866352400 + 115369081 = 62180^2 + 10741^2 .

It is a cyclic number.

It is not a de Polignac number, because 3981721481 - 2² = 3981721477 is a prime.

It is a super-2 number, since 2×3981721481² = 31708211904513666722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (3981721451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1990860740 + 1990860741.

It is an arithmetic number, because the mean of its divisors is an integer number (1990860741).

Almost surely, 2^3981721481 is an apocalyptic number.

It is an amenable number.

3981721481 is a deficient number, since it is larger than the sum of its proper divisors (1).

3981721481 is an equidigital number, since it uses as much as digits as its factorization.

3981721481 is an evil number, because the sum of its binary digits is even.

The product of its digits is 96768, while the sum is 44.

The square root of 3981721481 is about 63100.8833614871. The cubic root of 3981721481 is about 1584.9794145276.

The spelling of 3981721481 in words is "three billion, nine hundred eighty-one million, seven hundred twenty-one thousand, four hundred eighty-one".