21447668 has 12 divisors (see below), whose sum is σ = 40945632. Its totient is φ = 9748920.

The previous prime is 21447611. The next prime is 21447683. The reversal of 21447668 is 86674412.

It is a hoax number, since the sum of its digits (38) coincides with the sum of the digits of its distinct prime factors.

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, 243680 + ... + 243767.

It is an arithmetic number, because the mean of its divisors is an integer number (3412136).

Almost surely, 2^21447668 is an apocalyptic number.

It is an amenable number.

21447668 is a deficient number, since it is larger than the sum of its proper divisors (19497964).

21447668 is a wasteful number, since it uses less digits than its factorization.

21447668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 487462 (or 487460 counting only the distinct ones).

The product of its digits is 64512, while the sum is 38.

The square root of 21447668 is about 4631.1627049803. The cubic root of 21447668 is about 277.8390974078.

The spelling of 21447668 in words is "twenty-one million, four hundred forty-seven thousand, six hundred sixty-eight".