20866220 has 12 divisors (see below), whose sum is σ = 43819104. Its totient is φ = 8346480.

The previous prime is 20866211. The next prime is 20866229. The reversal of 20866220 is 2266802.

It is an interprime number because it is at equal distance from previous prime (20866211) and next prime (20866229).

It is a self number, because there is not a number n which added to its sum of digits gives 20866220.

It is not an unprimeable number, because it can be changed into a prime (20866229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 521636 + ... + 521675.

It is an arithmetic number, because the mean of its divisors is an integer number (3651592).

Almost surely, 2^20866220 is an apocalyptic number.

20866220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20866220 is an abundant number, since it is smaller than the sum of its proper divisors (22952884).

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

20866220 is a wasteful number, since it uses less digits than its factorization.

20866220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1043320 (or 1043318 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 26.

The square root of 20866220 is about 4567.9557791205. The cubic root of 20866220 is about 275.3053137980.

The spelling of 20866220 in words is "twenty million, eight hundred sixty-six thousand, two hundred twenty".