2172130661 has 4 divisors (see below), whose sum is σ = 2242199424. Its totient is φ = 2102061900.

The previous prime is 2172130633. The next prime is 2172130663. The reversal of 2172130661 is 1660312712.

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 a de Polignac number, because none of the positive numbers 2^k-2172130661 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 (2172130663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35034335 + ... + 35034396.

It is an arithmetic number, because the mean of its divisors is an integer number (560549856).

Almost surely, 2^2172130661 is an apocalyptic number.

It is an amenable number.

2172130661 is a deficient number, since it is larger than the sum of its proper divisors (70068763).

2172130661 is an equidigital number, since it uses as much as digits as its factorization.

2172130661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70068762.

The product of its (nonzero) digits is 3024, while the sum is 29.

The square root of 2172130661 is about 46606.1225698942. The cubic root of 2172130661 is about 1295.0761792368.

The spelling of 2172130661 in words is "two billion, one hundred seventy-two million, one hundred thirty thousand, six hundred sixty-one".