21035533221 has 20 divisors (see below), whose sum is σ = 32154234112. Its totient is φ = 13697554248.

The previous prime is 21035533201. The next prime is 21035533229. The reversal of 21035533221 is 12233553012.

It is a happy number.

21035533221 is a `hidden beast` number, since 2 + 103 + 5 + 533 + 2 + 21 = 666.

It is not a de Polignac number, because 21035533221 - 2¹¹ = 21035531173 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21035533229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 3016261 + ... + 3023226.

Almost surely, 2^21035533221 is an apocalyptic number.

It is an amenable number.

21035533221 is a deficient number, since it is larger than the sum of its proper divisors (11118700891).

21035533221 is an equidigital number, since it uses as much as digits as its factorization.

21035533221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6039542 (or 6039533 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 27.

The spelling of 21035533221 in words is "twenty-one billion, thirty-five million, five hundred thirty-three thousand, two hundred twenty-one".