21508073303 has 4 divisors (see below), whose sum is σ = 21508804440. Its totient is φ = 21507342168.

The previous prime is 21508073299. The next prime is 21508073333. The reversal of 21508073303 is 30337080512.

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 21508073303 - 2² = 21508073299 is a prime.

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 21508073303.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21508073333) 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 3 ways as a sum of consecutive naturals, for example, 319508 + ... + 380921.

It is an arithmetic number, because the mean of its divisors is an integer number (5377201110).

Almost surely, 2^21508073303 is an apocalyptic number.

21508073303 is a deficient number, since it is larger than the sum of its proper divisors (731137).

21508073303 is an equidigital number, since it uses as much as digits as its factorization.

21508073303 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 731136.

The product of its (nonzero) digits is 15120, while the sum is 32.

The spelling of 21508073303 in words is "twenty-one billion, five hundred eight million, seventy-three thousand, three hundred three".