21445440053 has 4 divisors (see below), whose sum is σ = 21463599948. Its totient is φ = 21427280160.

The previous prime is 21445440031. The next prime is 21445440061. The reversal of 21445440053 is 35004454412.

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

It can be written as a sum of positive squares in 2 ways, for example, as 19170340849 + 2275099204 = 138457^2 + 47698^2 .

It is a cyclic number.

It is not a de Polignac number, because 21445440053 - 2²⁴ = 21428662837 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 (21445440553) 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, 9078176 + ... + 9080537.

It is an arithmetic number, because the mean of its divisors is an integer number (5365899987).

Almost surely, 2^21445440053 is an apocalyptic number.

It is an amenable number.

21445440053 is a deficient number, since it is larger than the sum of its proper divisors (18159895).

21445440053 is a wasteful number, since it uses less digits than its factorization.

21445440053 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18159894.

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

Adding to 21445440053 its reverse (35004454412), we get a palindrome (56449894465).

The spelling of 21445440053 in words is "twenty-one billion, four hundred forty-five million, four hundred forty thousand, fifty-three".