21263352653 has 4 divisors (see below), whose sum is σ = 21996571740. Its totient is φ = 20530133568.

The previous prime is 21263352647. The next prime is 21263352661. The reversal of 21263352653 is 35625336212.

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 6539471689 + 14723880964 = 80867^2 + 121342^2 .

It is a cyclic number.

It is not a de Polignac number, because 21263352653 - 2⁶ = 21263352589 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 (21263352683) 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, 366609500 + ... + 366609557.

It is an arithmetic number, because the mean of its divisors is an integer number (5499142935).

Almost surely, 2^21263352653 is an apocalyptic number.

It is an amenable number.

21263352653 is a deficient number, since it is larger than the sum of its proper divisors (733219087).

21263352653 is an equidigital number, since it uses as much as digits as its factorization.

21263352653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 733219086.

The product of its digits is 194400, while the sum is 38.

Adding to 21263352653 its reverse (35625336212), we get a palindrome (56888688865).

The spelling of 21263352653 in words is "twenty-one billion, two hundred sixty-three million, three hundred fifty-two thousand, six hundred fifty-three".