21388085 has 8 divisors (see below), whose sum is σ = 25717920. Its totient is φ = 17075664.

The previous prime is 21388049. The next prime is 21388099. The reversal of 21388085 is 58088312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21388085 - 2¹⁰ = 21387061 is a prime.

It is a Curzon number.

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 7 ways as a sum of consecutive naturals, for example, 1475 + ... + 6704.

It is an arithmetic number, because the mean of its divisors is an integer number (3214740).

Almost surely, 2^21388085 is an apocalyptic number.

It is an amenable number.

21388085 is a deficient number, since it is larger than the sum of its proper divisors (4329835).

21388085 is an equidigital number, since it uses as much as digits as its factorization.

21388085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8707.

The product of its (nonzero) digits is 15360, while the sum is 35.

The square root of 21388085 is about 4624.7253972533. The cubic root of 21388085 is about 277.5815738323.

The spelling of 21388085 in words is "twenty-one million, three hundred eighty-eight thousand, eighty-five".