6381256865 has 4 divisors (see below), whose sum is σ = 7657508244. Its totient is φ = 5105005488.

The previous prime is 6381256757. The next prime is 6381256883. The reversal of 6381256865 is 5686521836.

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 1328748304 + 5052508561 = 36452^2 + 71081^2 .

It is a cyclic number.

It is not a de Polignac number, because 6381256865 - 2¹⁶ = 6381191329 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 638125682 + ... + 638125691.

It is an arithmetic number, because the mean of its divisors is an integer number (1914377061).

Almost surely, 2^6381256865 is an apocalyptic number.

It is an amenable number.

6381256865 is a deficient number, since it is larger than the sum of its proper divisors (1276251379).

6381256865 is a wasteful number, since it uses less digits than its factorization.

6381256865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1276251378.

The product of its digits is 2073600, while the sum is 50.

The square root of 6381256865 is about 79882.7695125801. The cubic root of 6381256865 is about 1854.8213044372.

The spelling of 6381256865 in words is "six billion, three hundred eighty-one million, two hundred fifty-six thousand, eight hundred sixty-five".