21221503243 has 4 divisors (see below), whose sum is σ = 21225758488. Its totient is φ = 21217248000.

The previous prime is 21221503241. The next prime is 21221503249. The reversal of 21221503243 is 34230512212.

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 21221503243 - 2¹ = 21221503241 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221503241) 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, 2120133 + ... + 2130118.

It is an arithmetic number, because the mean of its divisors is an integer number (5306439622).

Almost surely, 2^21221503243 is an apocalyptic number.

21221503243 is a deficient number, since it is larger than the sum of its proper divisors (4255245).

21221503243 is an equidigital number, since it uses as much as digits as its factorization.

21221503243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4255244.

The product of its (nonzero) digits is 2880, while the sum is 25.

The spelling of 21221503243 in words is "twenty-one billion, two hundred twenty-one million, five hundred three thousand, two hundred forty-three".