21030687 has 6 divisors (see below), whose sum is σ = 30377672. Its totient is φ = 14020452.

The previous prime is 21030677. The next prime is 21030703. The reversal of 21030687 is 78603012.

It is not a de Polignac number, because 21030687 - 2¹⁴ = 21014303 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21030687.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21030637) 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 5 ways as a sum of consecutive naturals, for example, 1168363 + ... + 1168380.

Almost surely, 2^21030687 is an apocalyptic number.

21030687 is a deficient number, since it is larger than the sum of its proper divisors (9346985).

21030687 is a wasteful number, since it uses less digits than its factorization.

21030687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2336749 (or 2336746 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 21030687 is about 4585.9226988688. The cubic root of 21030687 is about 276.0267381153.

Adding to 21030687 its reverse (78603012), we get a palindrome (99633699).

The spelling of 21030687 in words is "twenty-one million, thirty thousand, six hundred eighty-seven".