21424053561 has 16 divisors (see below), whose sum is σ = 28813048704. Its totient is φ = 14159164544.

The previous prime is 21424053557. The next prime is 21424053617. The reversal of 21424053561 is 16535042412.

It is a cyclic number.

It is not a de Polignac number, because 21424053561 - 2² = 21424053557 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21424055561) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 270295 + ... + 340451.

It is an arithmetic number, because the mean of its divisors is an integer number (1800815544).

Almost surely, 2^21424053561 is an apocalyptic number.

It is an amenable number.

21424053561 is a deficient number, since it is larger than the sum of its proper divisors (7388995143).

21424053561 is a wasteful number, since it uses less digits than its factorization.

21424053561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71040.

The product of its (nonzero) digits is 28800, while the sum is 33.

Adding to 21424053561 its reverse (16535042412), we get a palindrome (37959095973).

The spelling of 21424053561 in words is "twenty-one billion, four hundred twenty-four million, fifty-three thousand, five hundred sixty-one".