21313686 has 32 divisors (see below), whose sum is σ = 45577728. Its totient is φ = 6628160.

The previous prime is 21313679. The next prime is 21313693. The reversal of 21313686 is 68631312.

It is an interprime number because it is at equal distance from previous prime (21313679) and next prime (21313693).

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, 3775 + ... + 7541.

It is an arithmetic number, because the mean of its divisors is an integer number (1424304).

Almost surely, 2^21313686 is an apocalyptic number.

21313686 is an abundant number, since it is smaller than the sum of its proper divisors (24264042).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21313686 is a wasteful number, since it uses less digits than its factorization.

21313686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3836.

The product of its digits is 5184, while the sum is 30.

The square root of 21313686 is about 4616.6747773695. The cubic root of 21313686 is about 277.2593417137.

Adding to 21313686 its reverse (68631312), we get a palindrome (89944998).

The spelling of 21313686 in words is "twenty-one million, three hundred thirteen thousand, six hundred eighty-six".