21021550533 has 12 divisors (see below), whose sum is σ = 30705636780. Its totient is φ = 13856901696.

The previous prime is 21021550531. The next prime is 21021550547. The reversal of 21021550533 is 33505512012.

It is a happy number.

21021550533 is a `hidden beast` number, since 2 + 102 + 1 + 550 + 5 + 3 + 3 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 5282091684 + 15739458849 = 72678^2 + 125457^2 .

It is not a de Polignac number, because 21021550533 - 2¹ = 21021550531 is a prime.

It is a super-2 number, since 2×21021550533² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21021550497 and 21021550506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021550531) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13121266 + ... + 13122867.

It is an arithmetic number, because the mean of its divisors is an integer number (2558803065).

Almost surely, 2^21021550533 is an apocalyptic number.

It is an amenable number.

21021550533 is a deficient number, since it is larger than the sum of its proper divisors (9684086247).

21021550533 is a wasteful number, since it uses less digits than its factorization.

21021550533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26244228 (or 26244225 counting only the distinct ones).

The product of its (nonzero) digits is 4500, while the sum is 27.

The spelling of 21021550533 in words is "twenty-one billion, twenty-one million, five hundred fifty thousand, five hundred thirty-three".