2210521661 has 4 divisors (see below), whose sum is σ = 2210872032. Its totient is φ = 2210171292.

The previous prime is 2210521639. The next prime is 2210521711. The reversal of 2210521661 is 1661250122.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2210521661 - 2²⁶ = 2143412797 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2210521661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2210521361) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 165545 + ... + 178398.

It is an arithmetic number, because the mean of its divisors is an integer number (552718008).

Almost surely, 2^2210521661 is an apocalyptic number.

It is an amenable number.

2210521661 is a deficient number, since it is larger than the sum of its proper divisors (350371).

2210521661 is an equidigital number, since it uses as much as digits as its factorization.

2210521661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 350370.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 2210521661 is about 47016.1850961985. The cubic root of 2210521661 is about 1302.6615414821.

Adding to 2210521661 its reverse (1661250122), we get a palindrome (3871771783).

The spelling of 2210521661 in words is "two billion, two hundred ten million, five hundred twenty-one thousand, six hundred sixty-one".