3551821 has 16 divisors (see below), whose sum is σ = 4564224. Its totient is φ = 2686464.

The previous prime is 3551813. The next prime is 3551839. The reversal of 3551821 is 1281553.

It is a happy number.

3551821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 3551821 - 2³ = 3551813 is a prime.

It is a super-3 number, since 3×3551821³ (a number of 21 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3551851) 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 15 ways as a sum of consecutive naturals, for example, 1245 + ... + 2941.

It is an arithmetic number, because the mean of its divisors is an integer number (285264).

Almost surely, 2^3551821 is an apocalyptic number.

It is an amenable number.

3551821 is a deficient number, since it is larger than the sum of its proper divisors (1012403).

3551821 is a wasteful number, since it uses less digits than its factorization.

3551821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1740.

The product of its digits is 1200, while the sum is 25.

The square root of 3551821 is about 1884.6275494113. The cubic root of 3551821 is about 152.5751094669.

The spelling of 3551821 in words is "three million, five hundred fifty-one thousand, eight hundred twenty-one".