21808279329 has 4 divisors (see below), whose sum is σ = 29077705776. Its totient is φ = 14538852884.

The previous prime is 21808279319. The next prime is 21808279349. The reversal of 21808279329 is 92397280812.

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 21808279329 - 2¹³ = 21808271137 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21808279309) 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, 3634713219 + ... + 3634713224.

It is an arithmetic number, because the mean of its divisors is an integer number (7269426444).

Almost surely, 2^21808279329 is an apocalyptic number.

It is an amenable number.

21808279329 is a deficient number, since it is larger than the sum of its proper divisors (7269426447).

21808279329 is an equidigital number, since it uses as much as digits as its factorization.

21808279329 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7269426446.

The product of its (nonzero) digits is 870912, while the sum is 51.

The spelling of 21808279329 in words is "twenty-one billion, eight hundred eight million, two hundred seventy-nine thousand, three hundred twenty-nine".