2216601661 has 16 divisors (see below), whose sum is σ = 2417805936. Its totient is φ = 2023612416.

The previous prime is 2216601659. The next prime is 2216601691. The reversal of 2216601661 is 1661066122.

It can be written as a sum of positive squares in 8 ways, for example, as 493106436 + 1723495225 = 22206^2 + 41515^2 .

It is a cyclic number.

It is not a de Polignac number, because 2216601661 - 2¹ = 2216601659 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2216601641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 206745 + ... + 217201.

It is an arithmetic number, because the mean of its divisors is an integer number (151112871).

Almost surely, 2^2216601661 is an apocalyptic number.

It is an amenable number.

2216601661 is a deficient number, since it is larger than the sum of its proper divisors (201204275).

2216601661 is a wasteful number, since it uses less digits than its factorization.

2216601661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10848.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 2216601661 is about 47080.7992816605. The cubic root of 2216601661 is about 1303.8547638706.

Adding to 2216601661 its reverse (1661066122), we get a palindrome (3877667783).

The spelling of 2216601661 in words is "two billion, two hundred sixteen million, six hundred one thousand, six hundred sixty-one".