20257220 has 12 divisors (see below), whose sum is σ = 42540204. Its totient is φ = 8102880.

The previous prime is 20257219. The next prime is 20257247. The reversal of 20257220 is 2275202.

It can be written as a sum of positive squares in 2 ways, for example, as 12945604 + 7311616 = 3598^2 + 2704^2 .

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 1012861 = 20257220 / (2 + 0 + 2 + 5 + 7 + 2 + 2 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 20257192 and 20257201.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 506411 + ... + 506450.

It is an arithmetic number, because the mean of its divisors is an integer number (3545017).

Almost surely, 2^20257220 is an apocalyptic number.

20257220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20257220 is an abundant number, since it is smaller than the sum of its proper divisors (22282984).

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

20257220 is a wasteful number, since it uses less digits than its factorization.

20257220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1012870 (or 1012868 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 20.

The square root of 20257220 is about 4500.8021507282. The cubic root of 20257220 is about 272.6004791761.

The spelling of 20257220 in words is "twenty million, two hundred fifty-seven thousand, two hundred twenty".