203130021 has 4 divisors (see below), whose sum is σ = 270840032. Its totient is φ = 135420012.

The previous prime is 203129999. The next prime is 203130029. The reversal of 203130021 is 120031302.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 203130021 - 2⁵ = 203129989 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 203129979 and 203130006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (203130029) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33855001 + ... + 33855006.

It is an arithmetic number, because the mean of its divisors is an integer number (67710008).

Almost surely, 2^203130021 is an apocalyptic number.

It is an amenable number.

203130021 is a deficient number, since it is larger than the sum of its proper divisors (67710011).

203130021 is an equidigital number, since it uses as much as digits as its factorization.

203130021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67710010.

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 203130021 is about 14252.3689609833. The cubic root of 203130021 is about 587.8385153986.

Adding to 203130021 its reverse (120031302), we get a palindrome (323161323).

The spelling of 203130021 in words is "two hundred three million, one hundred thirty thousand, twenty-one".