3866809981 has 2 divisors, whose sum is σ = 3866809982. Its totient is φ = 3866809980.

The previous prime is 3866809939. The next prime is 3866810009. The reversal of 3866809981 is 1899086683.

3866809981 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3325828900 + 540981081 = 57670^2 + 23259^2 .

It is a cyclic number.

It is not a de Polignac number, because 3866809981 - 2¹⁷ = 3866678909 is a prime.

It is a super-2 number, since 2×3866809981² = 29904438858322440722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3866809901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1933404990 + 1933404991.

It is an arithmetic number, because the mean of its divisors is an integer number (1933404991).

Almost surely, 2^3866809981 is an apocalyptic number.

It is an amenable number.

3866809981 is a deficient number, since it is larger than the sum of its proper divisors (1).

3866809981 is an equidigital number, since it uses as much as digits as its factorization.

3866809981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4478976, while the sum is 58.

The square root of 3866809981 is about 62183.6793781134. The cubic root of 3866809981 is about 1569.5829664386.

The spelling of 3866809981 in words is "three billion, eight hundred sixty-six million, eight hundred nine thousand, nine hundred eighty-one".