21193866 has 32 divisors (see below), whose sum is σ = 49870080. Its totient is φ = 6648768.

The previous prime is 21193853. The next prime is 21193889. The reversal of 21193866 is 66839112.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21193866.

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, 10626 + ... + 12461.

It is an arithmetic number, because the mean of its divisors is an integer number (1558440).

Almost surely, 2^21193866 is an apocalyptic number.

21193866 is an abundant number, since it is smaller than the sum of its proper divisors (28676214).

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

21193866 is a wasteful number, since it uses less digits than its factorization.

21193866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23115 (or 23109 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 21193866 is about 4603.6796152643. The cubic root of 21193866 is about 276.7388050788.

The spelling of 21193866 in words is "twenty-one million, one hundred ninety-three thousand, eight hundred sixty-six".