21252054443 has 4 divisors (see below), whose sum is σ = 21255902328. Its totient is φ = 21248206560.

The previous prime is 21252054367. The next prime is 21252054457. The reversal of 21252054443 is 34445025212.

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 21252054443 - 2¹⁶ = 21251988907 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21252654443) 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, 1915646 + ... + 1926707.

It is an arithmetic number, because the mean of its divisors is an integer number (5313975582).

Almost surely, 2^21252054443 is an apocalyptic number.

21252054443 is a deficient number, since it is larger than the sum of its proper divisors (3847885).

21252054443 is an equidigital number, since it uses as much as digits as its factorization.

21252054443 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3847884.

The product of its (nonzero) digits is 38400, while the sum is 32.

Adding to 21252054443 its reverse (34445025212), we get a palindrome (55697079655).

The spelling of 21252054443 in words is "twenty-one billion, two hundred fifty-two million, fifty-four thousand, four hundred forty-three".