3865813 has 4 divisors (see below), whose sum is σ = 4418080. Its totient is φ = 3313548.

The previous prime is 3865801. The next prime is 3865819. The reversal of 3865813 is 3185683.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 3185683 = 839 ⋅3797.

It is not a de Polignac number, because 3865813 - 2¹³ = 3857621 is a prime.

It is a Duffinian number.

3865813 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3865819) 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, 276123 + ... + 276136.

It is an arithmetic number, because the mean of its divisors is an integer number (1104520).

Almost surely, 2^3865813 is an apocalyptic number.

It is an amenable number.

3865813 is a deficient number, since it is larger than the sum of its proper divisors (552267).

3865813 is an equidigital number, since it uses as much as digits as its factorization.

3865813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 552266.

The product of its digits is 17280, while the sum is 34.

The square root of 3865813 is about 1966.1670834392. The cubic root of 3865813 is about 156.9448059464.

The spelling of 3865813 in words is "three million, eight hundred sixty-five thousand, eight hundred thirteen".