21012027686 has 32 divisors (see below), whose sum is σ = 36181286400. Its totient is φ = 9071131680.

The previous prime is 21012027671. The next prime is 21012027697. The reversal of 21012027686 is 68672021012.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 230180 + ... + 308231.

It is an arithmetic number, because the mean of its divisors is an integer number (1130665200).

Almost surely, 2^21012027686 is an apocalyptic number.

21012027686 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21012027686 is a deficient number, since it is larger than the sum of its proper divisors (15169258714).

21012027686 is a wasteful number, since it uses less digits than its factorization.

21012027686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 538524.

The product of its (nonzero) digits is 16128, while the sum is 35.

Adding to 21012027686 its reverse (68672021012), we get a palindrome (89684048698).

The spelling of 21012027686 in words is "twenty-one billion, twelve million, twenty-seven thousand, six hundred eighty-six".