205130021 has 8 divisors (see below), whose sum is σ = 214189920. Its totient is φ = 196202608.

The previous prime is 205129997. The next prime is 205130111. The reversal of 205130021 is 120031502.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-205130021 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 205129978 and 205130005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205130221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29951 + ... + 36156.

It is an arithmetic number, because the mean of its divisors is an integer number (26773740).

Almost surely, 2^205130021 is an apocalyptic number.

It is an amenable number.

205130021 is a deficient number, since it is larger than the sum of its proper divisors (9059899).

205130021 is a wasteful number, since it uses less digits than its factorization.

205130021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66243.

The product of its (nonzero) digits is 60, while the sum is 14.

The square root of 205130021 is about 14322.3608738224. The cubic root of 205130021 is about 589.7614864699.

Adding to 205130021 its reverse (120031502), we get a palindrome (325161523).

The spelling of 205130021 in words is "two hundred five million, one hundred thirty thousand, twenty-one".