20655220 has 24 divisors (see below), whose sum is σ = 43482600. Its totient is φ = 8241792.

The previous prime is 20655203. The next prime is 20655227. The reversal of 20655220 is 2255602.

It can be written as a sum of positive squares in 4 ways, for example, as 11437924 + 9217296 = 3382^2 + 3036^2 .

It is a super-2 number, since 2×20655220² = 853276226496800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20655191 and 20655200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20655227) 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 7 ways as a sum of consecutive naturals, for example, 9166 + ... + 11194.

It is an arithmetic number, because the mean of its divisors is an integer number (1811775).

Almost surely, 2^20655220 is an apocalyptic number.

20655220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20655220 is an abundant number, since it is smaller than the sum of its proper divisors (22827380).

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

20655220 is a wasteful number, since it uses less digits than its factorization.

20655220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2547 (or 2545 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 22.

The square root of 20655220 is about 4544.8014258051. The cubic root of 20655220 is about 274.3742023420.

It can be divided in two parts, 20 and 655220, that multiplied together give a square (13104400 = 3620²).

The spelling of 20655220 in words is "twenty million, six hundred fifty-five thousand, two hundred twenty".