203121213021 has 24 divisors (see below), whose sum is σ = 308923105920. Its totient is φ = 128252258496.

The previous prime is 203121213017. The next prime is 203121213077. The reversal of 203121213021 is 120312121302.

It is not a de Polignac number, because 203121213021 - 2² = 203121213017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 203121212985 and 203121213003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (203121213121) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 477961 + ... + 796673.

It is an arithmetic number, because the mean of its divisors is an integer number (12871796080).

Almost surely, 2^203121213021 is an apocalyptic number.

It is an amenable number.

203121213021 is a deficient number, since it is larger than the sum of its proper divisors (105801892899).

203121213021 is a wasteful number, since it uses less digits than its factorization.

203121213021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322465 (or 322462 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 203121213021 its reverse (120312121302), we get a palindrome (323433334323).

The spelling of 203121213021 in words is "two hundred three billion, one hundred twenty-one million, two hundred thirteen thousand, twenty-one".