21221947583 has 4 divisors (see below), whose sum is σ = 21222676800. Its totient is φ = 21221218368.

The previous prime is 21221947493. The next prime is 21221947601. The reversal of 21221947583 is 38574912212.

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 21221947583 - 2¹⁶ = 21221882047 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221947183) 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, 319058 + ... + 379791.

It is an arithmetic number, because the mean of its divisors is an integer number (5305669200).

Almost surely, 2^21221947583 is an apocalyptic number.

21221947583 is a deficient number, since it is larger than the sum of its proper divisors (729217).

21221947583 is an equidigital number, since it uses as much as digits as its factorization.

21221947583 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 729216.

The product of its digits is 241920, while the sum is 44.

The spelling of 21221947583 in words is "twenty-one billion, two hundred twenty-one million, nine hundred forty-seven thousand, five hundred eighty-three".