205217240 has 32 divisors (see below), whose sum is σ = 462937680. Its totient is φ = 81873792.

The previous prime is 205217239. The next prime is 205217249. The reversal of 205217240 is 42712502.

It is a happy number.

It is a super-2 number, since 2×205217240² = 84228231186435200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205217249) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9419 + ... + 22341.

Almost surely, 2^205217240 is an apocalyptic number.

205217240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

205217240 is an abundant number, since it is smaller than the sum of its proper divisors (257720440).

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

205217240 is a wasteful number, since it uses less digits than its factorization.

205217240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13331 (or 13327 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 23.

The square root of 205217240 is about 14325.4054043856. The cubic root of 205217240 is about 589.8450612976.

Adding to 205217240 its reverse (42712502), we get a palindrome (247929742).

The spelling of 205217240 in words is "two hundred five million, two hundred seventeen thousand, two hundred forty".