21000203221 has 8 divisors (see below), whose sum is σ = 21123958464. Its totient is φ = 20876774400.

The previous prime is 21000203177. The next prime is 21000203233. The reversal of 21000203221 is 12230200012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21000203221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000206221) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48046 + ... + 210496.

It is an arithmetic number, because the mean of its divisors is an integer number (2640494808).

Almost surely, 2^21000203221 is an apocalyptic number.

It is an amenable number.

21000203221 is a deficient number, since it is larger than the sum of its proper divisors (123755243).

21000203221 is a wasteful number, since it uses less digits than its factorization.

21000203221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163211.

The product of its (nonzero) digits is 48, while the sum is 13.

Adding to 21000203221 its reverse (12230200012), we get a palindrome (33230403233).

The spelling of 21000203221 in words is "twenty-one billion, two hundred three thousand, two hundred twenty-one".