205218720 has 144 divisors (see below), whose sum is σ = 800392320. Its totient is φ = 46904832.

The previous prime is 205218707. The next prime is 205218737. The reversal of 205218720 is 27812502.

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-2 number, since 2×205218720² = 84229446076876800, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 100 + ... + 20259.

It is an arithmetic number, because the mean of its divisors is an integer number (5558280).

Almost surely, 2^205218720 is an apocalyptic number.

205218720 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 205218720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (400196160).

205218720 is an abundant number, since it is smaller than the sum of its proper divisors (595173600).

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

205218720 is a wasteful number, since it uses less digits than its factorization.

205218720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20387 (or 20376 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 205218720 is about 14325.4570607712. The cubic root of 205218720 is about 589.8464792561.

It can be divided in two parts, 20521 and 8720, that added together give a square (29241 = 171²).

The spelling of 205218720 in words is "two hundred five million, two hundred eighteen thousand, seven hundred twenty".