205221240 has 384 divisors, whose sum is σ = 819486720. Its totient is φ = 43545600.

The previous prime is 205221227. The next prime is 205221253. The reversal of 205221240 is 42122502.

205221240 is a `hidden beast` number, since 20 + 522 + 124 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (205221227) and next prime (205221253).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2890405 + ... + 2890475.

It is an arithmetic number, because the mean of its divisors is an integer number (2134080).

Almost surely, 2^205221240 is an apocalyptic number.

205221240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 205221240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (409743360).

205221240 is an abundant number, since it is smaller than the sum of its proper divisors (614265480).

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

205221240 is a wasteful number, since it uses less digits than its factorization.

205221240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163 (or 156 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

The square root of 205221240 is about 14325.5450158100. The cubic root of 205221240 is about 589.8488936022.

Adding to 205221240 its reverse (42122502), we get a palindrome (247343742).

It can be divided in two parts, 205 and 221240, that added together give a triangular number (221445 = T₆₆₅).

The spelling of 205221240 in words is "two hundred five million, two hundred twenty-one thousand, two hundred forty".