3221820 has 72 divisors (see below), whose sum is σ = 11173344. Its totient is φ = 736128.

The previous prime is 3221819. The next prime is 3221899. The reversal of 3221820 is 281223.

It is a happy number.

It is a super-2 number, since 2×3221820² = 20760248224800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 3221793 and 3221802.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19 + ... + 2538.

Almost surely, 2^3221820 is an apocalyptic number.

3221820 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 3221820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5586672).

3221820 is an abundant number, since it is smaller than the sum of its proper divisors (7951524).

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

3221820 is a wasteful number, since it uses less digits than its factorization.

3221820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2579 (or 2574 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 3221820 is about 1794.9428960276. The cubic root of 3221820 is about 147.6954413898.

The spelling of 3221820 in words is "three million, two hundred twenty-one thousand, eight hundred twenty".