21263333653 has 4 divisors (see below), whose sum is σ = 21273692908. Its totient is φ = 21252974400.

The previous prime is 21263333603. The next prime is 21263333657. The reversal of 21263333653 is 35633336212.

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 10850763889 + 10412569764 = 104167^2 + 102042^2 .

It is a cyclic number.

It is not a de Polignac number, because 21263333653 - 2¹⁷ = 21263202581 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 (21263333657) 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, 5176548 + ... + 5180653.

It is an arithmetic number, because the mean of its divisors is an integer number (5318423227).

Almost surely, 2^21263333653 is an apocalyptic number.

It is an amenable number.

21263333653 is a deficient number, since it is larger than the sum of its proper divisors (10359255).

21263333653 is a wasteful number, since it uses less digits than its factorization.

21263333653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10359254.

The product of its digits is 174960, while the sum is 37.

Adding to 21263333653 its reverse (35633336212), we get a palindrome (56896669865).

The spelling of 21263333653 in words is "twenty-one billion, two hundred sixty-three million, three hundred thirty-three thousand, six hundred fifty-three".