21066910919 has 4 divisors (see below), whose sum is σ = 21067636344. Its totient is φ = 21066185496.

The previous prime is 21066910903. The next prime is 21066910937. The reversal of 21066910919 is 91901966012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21066910919 - 2⁴ = 21066910903 is a prime.

It is a super-2 number, since 2×21066910919² (a number of 21 digits) contains 22 as substring.

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 21066910919.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21066910619) 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, 317252 + ... + 377865.

It is an arithmetic number, because the mean of its divisors is an integer number (5266909086).

Almost surely, 2^21066910919 is an apocalyptic number.

21066910919 is a deficient number, since it is larger than the sum of its proper divisors (725425).

21066910919 is an equidigital number, since it uses as much as digits as its factorization.

21066910919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 725424.

The product of its (nonzero) digits is 52488, while the sum is 44.

The spelling of 21066910919 in words is "twenty-one billion, sixty-six million, nine hundred ten thousand, nine hundred nineteen".