21040868 has 12 divisors (see below), whose sum is σ = 36854832. Its totient is φ = 10510920.

The previous prime is 21040807. The next prime is 21040879. The reversal of 21040868 is 86804012.

It is a self number, because there is not a number n which added to its sum of digits gives 21040868.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5483 + ... + 8493.

It is an arithmetic number, because the mean of its divisors is an integer number (3071236).

Almost surely, 2^21040868 is an apocalyptic number.

It is an amenable number.

21040868 is a deficient number, since it is larger than the sum of its proper divisors (15813964).

21040868 is a wasteful number, since it uses less digits than its factorization.

21040868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4762 (or 4760 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 29.

The square root of 21040868 is about 4587.0325919923. The cubic root of 21040868 is about 276.0712726387.

The spelling of 21040868 in words is "twenty-one million, forty thousand, eight hundred sixty-eight".