20666880 has 320 divisors, whose sum is σ = 82494720. Its totient is φ = 4866048.

The previous prime is 20666869. The next prime is 20666929. The reversal of 20666880 is 8866602.

It is a tau number, because it is divible by the number of its divisors (320).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a zygodrome in base 8.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 898549 + ... + 898571.

It is an arithmetic number, because the mean of its divisors is an integer number (257796).

Almost surely, 2^20666880 is an apocalyptic number.

20666880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20666880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41247360).

20666880 is an abundant number, since it is smaller than the sum of its proper divisors (61827840).

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

20666880 is a wasteful number, since it uses less digits than its factorization.

20666880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68 (or 46 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 20666880 is about 4546.0840291398. The cubic root of 20666880 is about 274.4258212774.

The spelling of 20666880 in words is "twenty million, six hundred sixty-six thousand, eight hundred eighty".