21204406236453 has 96 divisors (see below), whose sum is σ = 33805904283648. Its totient is φ = 11715796377600.

The previous prime is 21204406236449. The next prime is 21204406236479. The reversal of 21204406236453 is 35463260440212.

It is a happy number.

It is not a de Polignac number, because 21204406236453 - 2² = 21204406236449 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21204406036453) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 43235338 + ... + 43723028.

It is an arithmetic number, because the mean of its divisors is an integer number (352144836288).

Almost surely, 2^{21204406236453} is an apocalyptic number.

It is an amenable number.

21204406236453 is a deficient number, since it is larger than the sum of its proper divisors (12601498047195).

21204406236453 is a wasteful number, since it uses less digits than its factorization.

21204406236453 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 487883 (or 487866 counting only the distinct ones).

The product of its (nonzero) digits is 829440, while the sum is 42.

Adding to 21204406236453 its reverse (35463260440212), we get a palindrome (56667666676665).

The spelling of 21204406236453 in words is "twenty-one trillion, two hundred four billion, four hundred six million, two hundred thirty-six thousand, four hundred fifty-three".