203121021 has 16 divisors (see below), whose sum is σ = 280437248. Its totient is φ = 130636800.

The previous prime is 203121013. The next prime is 203121041. The reversal of 203121021 is 120121302.

It is not a de Polignac number, because 203121021 - 2³ = 203121013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 203120988 and 203121006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (203121041) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28101 + ... + 34581.

It is an arithmetic number, because the mean of its divisors is an integer number (17527328).

Almost surely, 2^203121021 is an apocalyptic number.

It is an amenable number.

203121021 is a deficient number, since it is larger than the sum of its proper divisors (77316227).

203121021 is a wasteful number, since it uses less digits than its factorization.

203121021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6852.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 203121021 is about 14252.0532205012. The cubic root of 203121021 is about 587.8298335623.

Adding to 203121021 its reverse (120121302), we get a palindrome (323242323).

The spelling of 203121021 in words is "two hundred three million, one hundred twenty-one thousand, twenty-one".