3856421 has 4 divisors (see below), whose sum is σ = 3876000. Its totient is φ = 3836844.

The previous prime is 3856409. The next prime is 3856451. The reversal of 3856421 is 1246583.

3856421 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: 1246583 = 13 ⋅95891.

It is a cyclic number.

It is not a de Polignac number, because 3856421 - 2⁶ = 3856357 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3856451) 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, 9491 + ... + 9888.

It is an arithmetic number, because the mean of its divisors is an integer number (969000).

Almost surely, 2^3856421 is an apocalyptic number.

It is an amenable number.

3856421 is a deficient number, since it is larger than the sum of its proper divisors (19579).

3856421 is a wasteful number, since it uses less digits than its factorization.

3856421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19578.

The product of its digits is 5760, while the sum is 29.

The square root of 3856421 is about 1963.7772276916. Note that the first 3 decimals coincide. The cubic root of 3856421 is about 156.8176036437.

The spelling of 3856421 in words is "three million, eight hundred fifty-six thousand, four hundred twenty-one".