21285693 has 64 divisors (see below), whose sum is σ = 38304000. Its totient is φ = 11508480.

The previous prime is 21285679. The next prime is 21285703. The reversal of 21285693 is 39658212.

It is not a de Polignac number, because 21285693 - 2⁹ = 21285181 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21285673) 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 63 ways as a sum of consecutive naturals, for example, 142783 + ... + 142931.

It is an arithmetic number, because the mean of its divisors is an integer number (598500).

Almost surely, 2^21285693 is an apocalyptic number.

It is an amenable number.

21285693 is a deficient number, since it is larger than the sum of its proper divisors (17018307).

21285693 is a wasteful number, since it uses less digits than its factorization.

21285693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 219 (or 213 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 21285693 is about 4613.6420537359. The cubic root of 21285693 is about 277.1379061083.

It can be divided in two parts, 212 and 85693, that added together give a triangular number (85905 = T₄₁₄).

The spelling of 21285693 in words is "twenty-one million, two hundred eighty-five thousand, six hundred ninety-three".