21864716 has 12 divisors (see below), whose sum is σ = 38307360. Its totient is φ = 10919760.

The previous prime is 21864659. The next prime is 21864757. The reversal of 21864716 is 61746812.

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, 1526 + ... + 6786.

It is an arithmetic number, because the mean of its divisors is an integer number (3192280).

Almost surely, 2^21864716 is an apocalyptic number.

It is an amenable number.

21864716 is a deficient number, since it is larger than the sum of its proper divisors (16442644).

21864716 is a wasteful number, since it uses less digits than its factorization.

21864716 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6304 (or 6302 counting only the distinct ones).

The product of its digits is 16128, while the sum is 35.

The square root of 21864716 is about 4675.9721983776. The cubic root of 21864716 is about 279.6284016140.

The spelling of 21864716 in words is "twenty-one million, eight hundred sixty-four thousand, seven hundred sixteen".