20866650 has 144 divisors (see below), whose sum is σ = 64120896. Its totient is φ = 4462080.

The previous prime is 20866649. The next prime is 20866661. The reversal of 20866650 is 5666802.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 124867 + ... + 125033.

It is an arithmetic number, because the mean of its divisors is an integer number (445284).

Almost surely, 2^20866650 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20866650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32060448).

20866650 is an abundant number, since it is smaller than the sum of its proper divisors (43254246).

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

20866650 is a wasteful number, since it uses less digits than its factorization.

20866650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213 (or 201 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 33.

The square root of 20866650 is about 4568.0028458835. The cubic root of 20866650 is about 275.3072049003.

The spelling of 20866650 in words is "twenty million, eight hundred sixty-six thousand, six hundred fifty".