2661326921 has 4 divisors (see below), whose sum is σ = 2903265744. Its totient is φ = 2419388100.

The previous prime is 2661326893. The next prime is 2661326923. The reversal of 2661326921 is 1296231662.

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 2661326921 - 2¹⁰ = 2661325897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2661326923) 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, 120969395 + ... + 120969416.

It is an arithmetic number, because the mean of its divisors is an integer number (725816436).

Almost surely, 2^2661326921 is an apocalyptic number.

It is an amenable number.

2661326921 is a deficient number, since it is larger than the sum of its proper divisors (241938823).

2661326921 is a wasteful number, since it uses less digits than its factorization.

2661326921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241938822.

The product of its digits is 46656, while the sum is 38.

The square root of 2661326921 is about 51588.0501763732. The cubic root of 2661326921 is about 1385.7963369940.

The spelling of 2661326921 in words is "two billion, six hundred sixty-one million, three hundred twenty-six thousand, nine hundred twenty-one".