3661220 has 24 divisors (see below), whose sum is σ = 7817208. Its totient is φ = 1440000.

The previous prime is 3661211. The next prime is 3661247. The reversal of 3661220 is 221663.

3661220 is nontrivially palindromic in base 11.

It can be written as a sum of positive squares in 4 ways, for example, as 5476 + 3655744 = 74^2 + 1912^2 .

It is a Smith number, since the sum of its digits (20) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 3661192 and 3661201.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 281 + ... + 2720.

It is an arithmetic number, because the mean of its divisors is an integer number (325717).

Almost surely, 2^3661220 is an apocalyptic number.

It is an amenable number.

3661220 is an abundant number, since it is smaller than the sum of its proper divisors (4155988).

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

3661220 is a wasteful number, since it uses less digits than its factorization.

3661220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3071 (or 3069 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 20.

The square root of 3661220 is about 1913.4314725121. The cubic root of 3661220 is about 154.1257756984.

Adding to 3661220 its reverse (221663), we get a palindrome (3882883).

The spelling of 3661220 in words is "three million, six hundred sixty-one thousand, two hundred twenty".