21533535 has 12 divisors (see below), whose sum is σ = 37324872. Its totient is φ = 11484528.

The previous prime is 21533527. The next prime is 21533579. The reversal of 21533535 is 53533512.

It is not a de Polignac number, because 21533535 - 2³ = 21533527 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21533499 and 21533508.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 239217 + ... + 239306.

It is an arithmetic number, because the mean of its divisors is an integer number (3110406).

Almost surely, 2^21533535 is an apocalyptic number.

21533535 is a deficient number, since it is larger than the sum of its proper divisors (15791337).

21533535 is a wasteful number, since it uses less digits than its factorization.

21533535 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 478534 (or 478531 counting only the distinct ones).

The product of its digits is 6750, while the sum is 27.

The square root of 21533535 is about 4640.4240107990. The cubic root of 21533535 is about 278.2093854113.

The spelling of 21533535 in words is "twenty-one million, five hundred thirty-three thousand, five hundred thirty-five".