865439381 has 4 divisors (see below), whose sum is σ = 867919500. Its totient is φ = 862959264.

The previous prime is 865439363. The next prime is 865439389. The reversal of 865439381 is 183934568.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 210540100 + 654899281 = 14510^2 + 25591^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-865439381 is a prime.

It is a super-2 number, since 2×865439381² = 1497970644371326322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (865439389) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1239536 + ... + 1240233.

It is an arithmetic number, because the mean of its divisors is an integer number (216979875).

Almost surely, 2^865439381 is an apocalyptic number.

It is an amenable number.

865439381 is a deficient number, since it is larger than the sum of its proper divisors (2480119).

865439381 is a wasteful number, since it uses less digits than its factorization.

865439381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2480118.

The product of its digits is 622080, while the sum is 47.

The square root of 865439381 is about 29418.3510924729. The cubic root of 865439381 is about 952.9692439720.

The spelling of 865439381 in words is "eight hundred sixty-five million, four hundred thirty-nine thousand, three hundred eighty-one".