205021000 has 64 divisors (see below), whose sum is σ = 487758960. Its totient is φ = 80640000.

The previous prime is 205020997. The next prime is 205021007. The reversal of 205021000 is 120502.

It can be written as a sum of positive squares in 8 ways, for example, as 15876 + 205005124 = 126^2 + 14318^2 .

It is a super-2 number, since 2×205021000² = 84067220882000000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is not an unprimeable number, because it can be changed into a prime (205021007) 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 15 ways as a sum of consecutive naturals, for example, 59320 + ... + 62680.

Almost surely, 2^205021000 is an apocalyptic number.

205021000 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 205021000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (243879480).

205021000 is an abundant number, since it is smaller than the sum of its proper divisors (282737960).

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

205021000 is a wasteful number, since it uses less digits than its factorization.

205021000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3443 (or 3429 counting only the distinct ones).

The product of its (nonzero) digits is 20, while the sum is 10.

The square root of 205021000 is about 14318.5543963069. The cubic root of 205021000 is about 589.6569872509.

Adding to 205021000 its reverse (120502), we get a palindrome (205141502).

The spelling of 205021000 in words is "two hundred five million, twenty-one thousand".