21030686 has 8 divisors (see below), whose sum is σ = 31608144. Its totient is φ = 10494640.

The previous prime is 21030677. The next prime is 21030703. The reversal of 21030686 is 68603012.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9050 + ... + 11133.

It is an arithmetic number, because the mean of its divisors is an integer number (3951018).

Almost surely, 2^21030686 is an apocalyptic number.

21030686 is a deficient number, since it is larger than the sum of its proper divisors (10577458).

21030686 is a wasteful number, since it uses less digits than its factorization.

21030686 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20706.

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 21030686 is about 4585.9225898395. The cubic root of 21030686 is about 276.0267337404.

Adding to 21030686 its reverse (68603012), we get a palindrome (89633698).

The spelling of 21030686 in words is "twenty-one million, thirty thousand, six hundred eighty-six".