3521221020 has 72 divisors (see below), whose sum is σ = 10779088320. Its totient is φ = 930372480.

The previous prime is 3521221001. The next prime is 3521221021. The reversal of 3521221020 is 201221253.

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

It is a junction number, because it is equal to n+sod(n) for n = 3521220984 and 3521221002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3521221021) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 70116 + ... + 109355.

It is an arithmetic number, because the mean of its divisors is an integer number (149709560).

Almost surely, 2^3521221020 is an apocalyptic number.

3521221020 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

3521221020 is an abundant number, since it is smaller than the sum of its proper divisors (7257867300).

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

3521221020 is a wasteful number, since it uses less digits than its factorization.

3521221020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179595 (or 179590 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 3521221020 is about 59339.8771485078. The cubic root of 3521221020 is about 1521.3568534033.

Adding to 3521221020 its reverse (201221253), we get a palindrome (3722442273).

The spelling of 3521221020 in words is "three billion, five hundred twenty-one million, two hundred twenty-one thousand, twenty".