20788866 has 64 divisors (see below), whose sum is σ = 54067200. Its totient is φ = 5797008.

The previous prime is 20788847. The next prime is 20788877. The reversal of 20788866 is 66888702.

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, 15615 + ... + 16893.

It is an arithmetic number, because the mean of its divisors is an integer number (844800).

Almost surely, 2^20788866 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20788866, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27033600).

20788866 is an abundant number, since it is smaller than the sum of its proper divisors (33278334).

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

20788866 is a wasteful number, since it uses less digits than its factorization.

20788866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1340 (or 1334 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 45.

The square root of 20788866 is about 4559.4808915051. The cubic root of 20788866 is about 274.9646940900.

The spelling of 20788866 in words is "twenty million, seven hundred eighty-eight thousand, eight hundred sixty-six".