3521820 has 48 divisors (see below), whose sum is σ = 9999360. Its totient is φ = 926016.

The previous prime is 3521803. The next prime is 3521831. The reversal of 3521820 is 281253.

3521820 = 277² + 278² + ... + 316².

It is a super-2 number, since 2×3521820² = 24806432224800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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, 4369 + ... + 5111.

It is an arithmetic number, because the mean of its divisors is an integer number (208320).

Almost surely, 2^3521820 is an apocalyptic number.

3521820 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 3521820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4999680).

3521820 is an abundant number, since it is smaller than the sum of its proper divisors (6477540).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

3521820 is a wasteful number, since it uses less digits than its factorization.

3521820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 834 (or 832 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 3521820 is about 1876.6512728794. The cubic root of 3521820 is about 152.1443112370.

The spelling of 3521820 in words is "three million, five hundred twenty-one thousand, eight hundred twenty".