21786135 has 24 divisors (see below), whose sum is σ = 40550256. Its totient is φ = 9959040.

The previous prime is 21786133. The next prime is 21786173. The reversal of 21786135 is 53168712.

It is not a de Polignac number, because 21786135 - 2¹ = 21786133 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21786096 and 21786105.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21786133) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 14086 + ... + 15555.

It is an arithmetic number, because the mean of its divisors is an integer number (1689594).

Almost surely, 2^21786135 is an apocalyptic number.

21786135 is a deficient number, since it is larger than the sum of its proper divisors (18764121).

21786135 is a wasteful number, since it uses less digits than its factorization.

21786135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29663 (or 29656 counting only the distinct ones).

The product of its digits is 10080, while the sum is 33.

The square root of 21786135 is about 4667.5619974458. The cubic root of 21786135 is about 279.2930080347.

The spelling of 21786135 in words is "twenty-one million, seven hundred eighty-six thousand, one hundred thirty-five".