2220100661 has 4 divisors (see below), whose sum is σ = 2226390252. Its totient is φ = 2213811072.

The previous prime is 2220100651. The next prime is 2220100699. The reversal of 2220100661 is 1660010222.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 298944100 + 1921156561 = 17290^2 + 43831^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2220100661 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2220100651) 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 3 ways as a sum of consecutive naturals, for example, 3144266 + ... + 3144971.

It is an arithmetic number, because the mean of its divisors is an integer number (556597563).

Almost surely, 2^2220100661 is an apocalyptic number.

It is an amenable number.

2220100661 is a deficient number, since it is larger than the sum of its proper divisors (6289591).

2220100661 is an equidigital number, since it uses as much as digits as its factorization.

2220100661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6289590.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 2220100661 is about 47117.9441508222. The cubic root of 2220100661 is about 1304.5404665938.

Adding to 2220100661 its reverse (1660010222), we get a palindrome (3880110883).

The spelling of 2220100661 in words is "two billion, two hundred twenty million, one hundred thousand, six hundred sixty-one".