21166716 has 48 divisors (see below), whose sum is σ = 52545024. Its totient is φ = 6616896.

The previous prime is 21166711. The next prime is 21166721. The reversal of 21166716 is 61766112.

It is an interprime number because it is at equal distance from previous prime (21166711) and next prime (21166721).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21166711) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13905 + ... + 15351.

It is an arithmetic number, because the mean of its divisors is an integer number (1094688).

Almost surely, 2^21166716 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21166716, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26272512).

21166716 is an abundant number, since it is smaller than the sum of its proper divisors (31378308).

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

21166716 is a wasteful number, since it uses less digits than its factorization.

21166716 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1530 (or 1528 counting only the distinct ones).

The product of its digits is 3024, while the sum is 30.

The square root of 21166716 is about 4600.7299420853. The cubic root of 21166716 is about 276.6205842507.

The spelling of 21166716 in words is "twenty-one million, one hundred sixty-six thousand, seven hundred sixteen".