205021660 has 12 divisors (see below), whose sum is σ = 430545528. Its totient is φ = 82008656.

The previous prime is 205021657. The next prime is 205021667. The reversal of 205021660 is 66120502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205021667) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 5125522 + ... + 5125561.

It is an arithmetic number, because the mean of its divisors is an integer number (35878794).

Almost surely, 2^205021660 is an apocalyptic number.

205021660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

205021660 is an abundant number, since it is smaller than the sum of its proper divisors (225523868).

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

205021660 is a wasteful number, since it uses less digits than its factorization.

205021660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10251092 (or 10251090 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 205021660 is about 14318.5774433077. The cubic root of 205021660 is about 589.6576199881.

The spelling of 205021660 in words is "two hundred five million, twenty-one thousand, six hundred sixty".