3861891565 has 16 divisors (see below), whose sum is σ = 5338017792. Its totient is φ = 2627299584.

The previous prime is 3861891563. The next prime is 3861891571. The reversal of 3861891565 is 5651981683.

It is not a de Polignac number, because 3861891565 - 2¹ = 3861891563 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3861891563) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 429964 + ... + 438853.

It is an arithmetic number, because the mean of its divisors is an integer number (333626112).

Almost surely, 2^3861891565 is an apocalyptic number.

3861891565 is a gapful number since it is divisible by the number (35) formed by its first and last digit.

It is an amenable number.

3861891565 is a deficient number, since it is larger than the sum of its proper divisors (1476126227).

3861891565 is a wasteful number, since it uses less digits than its factorization.

3861891565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 868956.

The product of its digits is 1555200, while the sum is 52.

The square root of 3861891565 is about 62144.1193114843. The cubic root of 3861891565 is about 1568.9172034075.

The spelling of 3861891565 in words is "three billion, eight hundred sixty-one million, eight hundred ninety-one thousand, five hundred sixty-five".