21716716 has 24 divisors (see below), whose sum is σ = 44495136. Its totient is φ = 9079680.

The previous prime is 21716713. The next prime is 21716729. The reversal of 21716716 is 61761712.

It is not an unprimeable number, because it can be changed into a prime (21716713) 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, 8311 + ... + 10606.

It is an arithmetic number, because the mean of its divisors is an integer number (1853964).

Almost surely, 2^21716716 is an apocalyptic number.

It is an amenable number.

21716716 is an abundant number, since it is smaller than the sum of its proper divisors (22778420).

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

21716716 is a wasteful number, since it uses less digits than its factorization.

21716716 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18969 (or 18967 counting only the distinct ones).

The product of its digits is 3528, while the sum is 31.

The square root of 21716716 is about 4660.1197409509. The cubic root of 21716716 is about 278.9960474425.

The spelling of 21716716 in words is "twenty-one million, seven hundred sixteen thousand, seven hundred sixteen".