21261035533 has 6 divisors (see below), whose sum is σ = 22585252586. Its totient is φ = 20010386112.

The previous prime is 21261035513. The next prime is 21261035561. The reversal of 21261035533 is 33553016212.

It can be written as a sum of positive squares in 3 ways, for example, as 6825733924 + 14435301609 = 82618^2 + 120147^2 .

It is not a de Polignac number, because 21261035533 - 2²⁹ = 20724164621 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21261035495 and 21261035504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21261035513) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 36783510 + ... + 36784087.

Almost surely, 2^21261035533 is an apocalyptic number.

It is an amenable number.

21261035533 is a deficient number, since it is larger than the sum of its proper divisors (1324217053).

21261035533 is an equidigital number, since it uses as much as digits as its factorization.

21261035533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73567631 (or 73567614 counting only the distinct ones).

The product of its (nonzero) digits is 16200, while the sum is 31.

The spelling of 21261035533 in words is "twenty-one billion, two hundred sixty-one million, thirty-five thousand, five hundred thirty-three".