21036686 has 32 divisors (see below), whose sum is σ = 36892800. Its totient is φ = 8894880.

The previous prime is 21036671. The next prime is 21036689. The reversal of 21036686 is 68663012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21036689) 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 15 ways as a sum of consecutive naturals, for example, 24236 + ... + 25088.

It is an arithmetic number, because the mean of its divisors is an integer number (1152900).

Almost surely, 2^21036686 is an apocalyptic number.

21036686 is a deficient number, since it is larger than the sum of its proper divisors (15856114).

21036686 is a wasteful number, since it uses less digits than its factorization.

21036686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 944.

The product of its (nonzero) digits is 10368, while the sum is 32.

The square root of 21036686 is about 4586.5767190793. The cubic root of 21036686 is about 276.0529811474.

Adding to 21036686 its reverse (68663012), we get a palindrome (89699698).

The spelling of 21036686 in words is "twenty-one million, thirty-six thousand, six hundred eighty-six".