3811821 has 16 divisors (see below), whose sum is σ = 5603136. Its totient is φ = 2290176.

The previous prime is 3811817. The next prime is 3811877. The reversal of 3811821 is 1281183.

It is not a de Polignac number, because 3811821 - 2² = 3811817 is a prime.

It is an Ulam number.

3811821 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 3811791 and 3811800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3811891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 541 + ... + 2813.

It is an arithmetic number, because the mean of its divisors is an integer number (350196).

Almost surely, 2^3811821 is an apocalyptic number.

It is an amenable number.

3811821 is a deficient number, since it is larger than the sum of its proper divisors (1791315).

3811821 is a wasteful number, since it uses less digits than its factorization.

3811821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2332.

The product of its digits is 384, while the sum is 24.

The square root of 3811821 is about 1952.3885371514. The cubic root of 3811821 is about 156.2107195126.

It can be divided in two parts, 381182 and 1, that added together give a palindrome (381183).

The spelling of 3811821 in words is "three million, eight hundred eleven thousand, eight hundred twenty-one".