3866521 has 4 divisors (see below), whose sum is σ = 3900852. Its totient is φ = 3832192.

The previous prime is 3866479. The next prime is 3866543. The reversal of 3866521 is 1256683.

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 1792921 + 2073600 = 1339^2 + 1440^2 .

It is a cyclic number.

It is not a de Polignac number, because 3866521 - 2⁷ = 3866393 is a prime.

It is a Duffinian number.

3866521 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (3866581) 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, 16996 + ... + 17221.

It is an arithmetic number, because the mean of its divisors is an integer number (975213).

Almost surely, 2^3866521 is an apocalyptic number.

It is an amenable number.

3866521 is a deficient number, since it is larger than the sum of its proper divisors (34331).

3866521 is a wasteful number, since it uses less digits than its factorization.

3866521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34330.

The product of its digits is 8640, while the sum is 31.

The square root of 3866521 is about 1966.3471209326. The cubic root of 3866521 is about 156.9543865219.

The spelling of 3866521 in words is "three million, eight hundred sixty-six thousand, five hundred twenty-one".