21068668 has 24 divisors (see below), whose sum is σ = 37983680. Its totient is φ = 10221120.

The previous prime is 21068659. The next prime is 21068669. The reversal of 21068668 is 86686012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21068669) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18730 + ... + 19822.

Almost surely, 2^21068668 is an apocalyptic number.

It is an amenable number.

21068668 is a deficient number, since it is larger than the sum of its proper divisors (16915012).

21068668 is a wasteful number, since it uses less digits than its factorization.

21068668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1237 (or 1235 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 37.

The square root of 21068668 is about 4590.0618732213. The cubic root of 21068668 is about 276.1928044403.

It can be divided in two parts, 21068 and 668, that added together give a triangular number (21736 = T₂₀₈).

The spelling of 21068668 in words is "twenty-one million, sixty-eight thousand, six hundred sixty-eight".