205217320 has 64 divisors (see below), whose sum is σ = 575683200. Its totient is φ = 63962880.

The previous prime is 205217317. The next prime is 205217321. The reversal of 205217320 is 23712502.

205217320 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×205217320² = 84228296855964800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a junction number, because it is equal to n+sod(n) for n = 205217291 and 205217300.

It is not an unprimeable number, because it can be changed into a prime (205217321) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30235 + ... + 36394.

It is an arithmetic number, because the mean of its divisors is an integer number (8995050).

Almost surely, 2^205217320 is an apocalyptic number.

205217320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

205217320 is an abundant number, since it is smaller than the sum of its proper divisors (370465880).

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

205217320 is a wasteful number, since it uses less digits than its factorization.

205217320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66658 (or 66654 counting only the distinct ones).

The product of its (nonzero) digits is 840, while the sum is 22.

The square root of 205217320 is about 14325.4081966274. The cubic root of 205217320 is about 589.8451379442.

Adding to 205217320 its reverse (23712502), we get a palindrome (228929822).

The spelling of 205217320 in words is "two hundred five million, two hundred seventeen thousand, three hundred twenty".