21523052443 has 4 divisors (see below), whose sum is σ = 21617867880. Its totient is φ = 21428237008.

The previous prime is 21523052417. The next prime is 21523052449. The reversal of 21523052443 is 34425032512.

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 21523052443 - 2²⁵ = 21489498011 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21523052449) 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, 47407378 + ... + 47407831.

It is an arithmetic number, because the mean of its divisors is an integer number (5404466970).

Almost surely, 2^21523052443 is an apocalyptic number.

21523052443 is a deficient number, since it is larger than the sum of its proper divisors (94815437).

21523052443 is an equidigital number, since it uses as much as digits as its factorization.

21523052443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94815436.

The product of its (nonzero) digits is 28800, while the sum is 31.

Adding to 21523052443 its reverse (34425032512), we get a palindrome (55948084955).

The spelling of 21523052443 in words is "twenty-one billion, five hundred twenty-three million, fifty-two thousand, four hundred forty-three".