3865387981 has 48 divisors (see below), whose sum is σ = 5082787584. Its totient is φ = 2908071936.

The previous prime is 3865387979. The next prime is 3865387991. The reversal of 3865387981 is 1897835683.

It is not a de Polignac number, because 3865387981 - 2¹ = 3865387979 is a prime.

It is a super-2 number, since 2×3865387981² = 29882448487318512722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3865387901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2826960 + ... + 2828326.

It is an arithmetic number, because the mean of its divisors is an integer number (105891408).

Almost surely, 2^3865387981 is an apocalyptic number.

It is an amenable number.

3865387981 is a deficient number, since it is larger than the sum of its proper divisors (1217399603).

3865387981 is a wasteful number, since it uses less digits than its factorization.

3865387981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1610 (or 1603 counting only the distinct ones).

The product of its digits is 8709120, while the sum is 58.

The square root of 3865387981 is about 62172.2444584398. The cubic root of 3865387981 is about 1569.3905407577.

The spelling of 3865387981 in words is "three billion, eight hundred sixty-five million, three hundred eighty-seven thousand, nine hundred eighty-one".