21007085 has 16 divisors (see below), whose sum is σ = 27656640. Its totient is φ = 15191040.

The previous prime is 21007069. The next prime is 21007099. The reversal of 21007085 is 58070012.

It is not a de Polignac number, because 21007085 - 2⁴ = 21007069 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21007085.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9626 + ... + 11604.

It is an arithmetic number, because the mean of its divisors is an integer number (1728540).

Almost surely, 2^21007085 is an apocalyptic number.

It is an amenable number.

21007085 is a deficient number, since it is larger than the sum of its proper divisors (6649555).

21007085 is a wasteful number, since it uses less digits than its factorization.

21007085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2188.

The product of its (nonzero) digits is 560, while the sum is 23.

The square root of 21007085 is about 4583.3486666410. The cubic root of 21007085 is about 275.9234410983.

Adding to 21007085 its reverse (58070012), we get a palindrome (79077097).

The spelling of 21007085 in words is "twenty-one million, seven thousand, eighty-five".