203121031321 has 4 divisors (see below), whose sum is σ = 218745726052. Its totient is φ = 187496336592.

The previous prime is 203121031307. The next prime is 203121031349. The reversal of 203121031321 is 123130121302.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 123130121302 = 2 ⋅61565060651.

It can be written as a sum of positive squares in 2 ways, for example, as 64391600025 + 138729431296 = 253755^2 + 372464^2 .

It is a cyclic number.

It is not a de Polignac number, because 203121031321 - 2⁹ = 203121030809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (203121031121) 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, 7812347346 + ... + 7812347371.

It is an arithmetic number, because the mean of its divisors is an integer number (54686431513).

Almost surely, 2^203121031321 is an apocalyptic number.

It is an amenable number.

203121031321 is a deficient number, since it is larger than the sum of its proper divisors (15624694731).

203121031321 is a wasteful number, since it uses less digits than its factorization.

203121031321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15624694730.

The product of its (nonzero) digits is 216, while the sum is 19.

Adding to 203121031321 its reverse (123130121302), we get a palindrome (326251152623).

The spelling of 203121031321 in words is "two hundred three billion, one hundred twenty-one million, thirty-one thousand, three hundred twenty-one".