21069686 has 16 divisors (see below), whose sum is σ = 34637760. Its totient is φ = 9532680.

The previous prime is 21069683. The next prime is 21069701. The reversal of 21069686 is 68696012.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21069683) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2885 + ... + 7103.

It is an arithmetic number, because the mean of its divisors is an integer number (2164860).

Almost surely, 2^21069686 is an apocalyptic number.

21069686 is a deficient number, since it is larger than the sum of its proper divisors (13568074).

21069686 is a wasteful number, since it uses less digits than its factorization.

21069686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4459.

The product of its (nonzero) digits is 31104, while the sum is 38.

The square root of 21069686 is about 4590.1727636332. The cubic root of 21069686 is about 276.1972527479.

It can be divided in two parts, 210 and 69686, that added together give a palindrome (69896).

The spelling of 21069686 in words is "twenty-one million, sixty-nine thousand, six hundred eighty-six".