2105665521 has 8 divisors (see below), whose sum is σ = 2823783360. Its totient is φ = 1395662352.

The previous prime is 2105665517. The next prime is 2105665537. The reversal of 2105665521 is 1255665012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2105665521 - 2² = 2105665517 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2105665501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2028061 + ... + 2029098.

It is an arithmetic number, because the mean of its divisors is an integer number (352972920).

Almost surely, 2^2105665521 is an apocalyptic number.

It is an amenable number.

2105665521 is a deficient number, since it is larger than the sum of its proper divisors (718117839).

2105665521 is a wasteful number, since it uses less digits than its factorization.

2105665521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4057335.

The product of its (nonzero) digits is 18000, while the sum is 33.

The square root of 2105665521 is about 45887.5312149172. The cubic root of 2105665521 is about 1281.7297417236.

The spelling of 2105665521 in words is "two billion, one hundred five million, six hundred sixty-five thousand, five hundred twenty-one".