20688220 has 24 divisors (see below), whose sum is σ = 49652064. Its totient is φ = 7093056.

The previous prime is 20688209. The next prime is 20688251. The reversal of 20688220 is 2288602.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 73747 + ... + 74026.

It is an arithmetic number, because the mean of its divisors is an integer number (2068836).

Almost surely, 2^20688220 is an apocalyptic number.

20688220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20688220 is an abundant number, since it is smaller than the sum of its proper divisors (28963844).

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

20688220 is a wasteful number, since it uses less digits than its factorization.

20688220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147789 (or 147787 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 28.

The square root of 20688220 is about 4548.4304985346. The cubic root of 20688220 is about 274.5202434078.

The spelling of 20688220 in words is "twenty million, six hundred eighty-eight thousand, two hundred twenty".