3856618681 has 2 divisors, whose sum is σ = 3856618682. Its totient is φ = 3856618680.

The previous prime is 3856618663. The next prime is 3856618693. The reversal of 3856618681 is 1868166583.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3123021456 + 733597225 = 55884^2 + 27085^2 .

It is a cyclic number.

It is not a de Polignac number, because 3856618681 - 2⁷ = 3856618553 is a prime.

It is a super-2 number, since 2×3856618681² = 29747015301276359522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (3856618781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1928309340 + 1928309341.

It is an arithmetic number, because the mean of its divisors is an integer number (1928309341).

Almost surely, 2^3856618681 is an apocalyptic number.

It is an amenable number.

3856618681 is a deficient number, since it is larger than the sum of its proper divisors (1).

3856618681 is an equidigital number, since it uses as much as digits as its factorization.

3856618681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1658880, while the sum is 52.

The square root of 3856618681 is about 62101.6801785588. The cubic root of 3856618681 is about 1568.2028309964.

The spelling of 3856618681 in words is "three billion, eight hundred fifty-six million, six hundred eighteen thousand, six hundred eighty-one".