21161286 has 12 divisors (see below), whose sum is σ = 45849492. Its totient is φ = 7053756.

The previous prime is 21161281. The next prime is 21161297. The reversal of 21161286 is 68216112.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21161281) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 587796 + ... + 587831.

It is an arithmetic number, because the mean of its divisors is an integer number (3820791).

Almost surely, 2^21161286 is an apocalyptic number.

21161286 is an abundant number, since it is smaller than the sum of its proper divisors (24688206).

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

21161286 is a wasteful number, since it uses less digits than its factorization.

21161286 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1175635 (or 1175632 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 21161286 is about 4600.1397804849. The cubic root of 21161286 is about 276.5969279557.

Adding to 21161286 its reverse (68216112), we get a palindrome (89377398).

The spelling of 21161286 in words is "twenty-one million, one hundred sixty-one thousand, two hundred eighty-six".