205215220 has 24 divisors (see below), whose sum is σ = 492516864. Its totient is φ = 70359456.

The previous prime is 205215217. The next prime is 205215229. The reversal of 205215220 is 22512502.

It is a super-2 number, since 2×205215220² = 84226573039296800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205215229) 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, 732772 + ... + 733051.

It is an arithmetic number, because the mean of its divisors is an integer number (20521536).

Almost surely, 2^205215220 is an apocalyptic number.

205215220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

205215220 is an abundant number, since it is smaller than the sum of its proper divisors (287301644).

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

205215220 is a wasteful number, since it uses less digits than its factorization.

205215220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1465839 (or 1465837 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 19.

The square root of 205215220 is about 14325.3349000992. The cubic root of 205215220 is about 589.8431259649.

Adding to 205215220 its reverse (22512502), we get a palindrome (227727722).

The spelling of 205215220 in words is "two hundred five million, two hundred fifteen thousand, two hundred twenty".