3856521 has 4 divisors (see below), whose sum is σ = 5142032. Its totient is φ = 2571012.

The previous prime is 3856519. The next prime is 3856537. The reversal of 3856521 is 1256583.

3856521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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: 1256583 = 3 ⋅418861.

It is not a de Polignac number, because 3856521 - 2¹ = 3856519 is a prime.

It is a D-number.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3856511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 642751 + ... + 642756.

It is an arithmetic number, because the mean of its divisors is an integer number (1285508).

Almost surely, 2^3856521 is an apocalyptic number.

It is an amenable number.

3856521 is a deficient number, since it is larger than the sum of its proper divisors (1285511).

3856521 is a wasteful number, since it uses less digits than its factorization.

3856521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1285510.

The product of its digits is 7200, while the sum is 30.

The square root of 3856521 is about 1963.8026886630. The cubic root of 3856521 is about 156.8189590995.

The spelling of 3856521 in words is "three million, eight hundred fifty-six thousand, five hundred twenty-one".