205531020 has 180 divisors, whose sum is σ = 686476560. Its totient is φ = 51466752.

The previous prime is 205531019. The next prime is 205531049. The reversal of 205531020 is 20135502.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (180).

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

It is a junction number, because it is equal to n+sod(n) for n = 205530984 and 205531002.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 467961 + ... + 468399.

Almost surely, 2^205531020 is an apocalyptic number.

205531020 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 205531020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (343238280).

205531020 is an abundant number, since it is smaller than the sum of its proper divisors (480945540).

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

205531020 is a wasteful number, since it uses less digits than its factorization.

205531020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 494 (or 466 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 18.

The square root of 205531020 is about 14336.3530927499. The cubic root of 205531020 is about 590.1455352939.

Adding to 205531020 its reverse (20135502), we get a palindrome (225666522).

The spelling of 205531020 in words is "two hundred five million, five hundred thirty-one thousand, twenty".