21068756 has 12 divisors (see below), whose sum is σ = 37058868. Its totient is φ = 10480512.

The previous prime is 21068741. The next prime is 21068807. The reversal of 21068756 is 65786012.

It can be written as a sum of positive squares in 2 ways, for example, as 18232900 + 2835856 = 4270^2 + 1684^2 .

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 12581 + ... + 14156.

It is an arithmetic number, because the mean of its divisors is an integer number (3088239).

Almost surely, 2^21068756 is an apocalyptic number.

It is an amenable number.

21068756 is a deficient number, since it is larger than the sum of its proper divisors (15990112).

21068756 is a wasteful number, since it uses less digits than its factorization.

21068756 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26938 (or 26936 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 35.

The square root of 21068756 is about 4590.0714591387. The cubic root of 21068756 is about 276.1931889755.

The spelling of 21068756 in words is "twenty-one million, sixty-eight thousand, seven hundred fifty-six".