20721503203 has 4 divisors (see below), whose sum is σ = 20755307248. Its totient is φ = 20687699160.

The previous prime is 20721503177. The next prime is 20721503233. The reversal of 20721503203 is 30230512702.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20721503203 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20721503233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16901103 + ... + 16902328.

It is an arithmetic number, because the mean of its divisors is an integer number (5188826812).

Almost surely, 2^20721503203 is an apocalyptic number.

20721503203 is a deficient number, since it is larger than the sum of its proper divisors (33804045).

20721503203 is an equidigital number, since it uses as much as digits as its factorization.

20721503203 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33804044.

The product of its (nonzero) digits is 2520, while the sum is 25.

The spelling of 20721503203 in words is "twenty billion, seven hundred twenty-one million, five hundred three thousand, two hundred three".