203440021 has 4 divisors (see below), whose sum is σ = 204505344. Its totient is φ = 202374700.

The previous prime is 203440019. The next prime is 203440031. The reversal of 203440021 is 120044302.

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 a cyclic number.

It is not a de Polignac number, because 203440021 - 2¹ = 203440019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 203439977 and 203440004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (203440031) 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 3 ways as a sum of consecutive naturals, for example, 532375 + ... + 532756.

It is an arithmetic number, because the mean of its divisors is an integer number (51126336).

Almost surely, 2^203440021 is an apocalyptic number.

It is an amenable number.

203440021 is a deficient number, since it is larger than the sum of its proper divisors (1065323).

203440021 is a wasteful number, since it uses less digits than its factorization.

203440021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1065322.

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 203440021 is about 14263.2401998985. The cubic root of 203440021 is about 588.1374000178.

Adding to 203440021 its reverse (120044302), we get a palindrome (323484323).

The spelling of 203440021 in words is "two hundred three million, four hundred forty thousand, twenty-one".