21001203321 has 16 divisors (see below), whose sum is σ = 32164285824. Its totient is φ = 11939768064.

The previous prime is 21001203313. The next prime is 21001203323. The reversal of 21001203321 is 12330210012.

It is not a de Polignac number, because 21001203321 - 2³ = 21001203313 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21001203321.

It is not an unprimeable number, because it can be changed into a prime (21001203323) 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, 2534080 + ... + 2542353.

It is an arithmetic number, because the mean of its divisors is an integer number (2010267864).

Almost surely, 2^21001203321 is an apocalyptic number.

21001203321 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21001203321 is a deficient number, since it is larger than the sum of its proper divisors (11163082503).

21001203321 is a wasteful number, since it uses less digits than its factorization.

21001203321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5076640.

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 21001203321 its reverse (12330210012), we get a palindrome (33331413333).

The spelling of 21001203321 in words is "twenty-one billion, one million, two hundred three thousand, three hundred twenty-one".