21766533 has 16 divisors (see below), whose sum is σ = 31879680. Its totient is φ = 13148784.

The previous prime is 21766513. The next prime is 21766543. The reversal of 21766533 is 33566712.

It is not a de Polignac number, because 21766533 - 2¹² = 21762437 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21766494 and 21766503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21766513) 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, 6991 + ... + 9612.

It is an arithmetic number, because the mean of its divisors is an integer number (1992480).

Almost surely, 2^21766533 is an apocalyptic number.

21766533 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21766533 is a deficient number, since it is larger than the sum of its proper divisors (10113147).

21766533 is a wasteful number, since it uses less digits than its factorization.

21766533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16648.

The product of its digits is 22680, while the sum is 33.

The square root of 21766533 is about 4665.4617134856. The cubic root of 21766533 is about 279.2092185923.

The spelling of 21766533 in words is "twenty-one million, seven hundred sixty-six thousand, five hundred thirty-three".