21263154503653 has 4 divisors (see below), whose sum is σ = 21273727929088. Its totient is φ = 21252581078220.

The previous prime is 21263154503629. The next prime is 21263154503659. The reversal of 21263154503653 is 35630545136212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21263154503653 - 2²⁵ = 21263120949221 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 (21263154503659) 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, 5286709701 + ... + 5286713722.

It is an arithmetic number, because the mean of its divisors is an integer number (5318431982272).

Almost surely, 2^{21263154503653} is an apocalyptic number.

It is an amenable number.

21263154503653 is a deficient number, since it is larger than the sum of its proper divisors (10573425435).

21263154503653 is a wasteful number, since it uses less digits than its factorization.

21263154503653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10573425434.

The product of its (nonzero) digits is 1944000, while the sum is 46.

Adding to 21263154503653 its reverse (35630545136212), we get a palindrome (56893699639865).

The spelling of 21263154503653 in words is "twenty-one trillion, two hundred sixty-three billion, one hundred fifty-four million, five hundred three thousand, six hundred fifty-three".