21001203211 has 4 divisors (see below), whose sum is σ = 21030824800. Its totient is φ = 20971581624.

The previous prime is 21001203199. The next prime is 21001203221. The reversal of 21001203211 is 11230210012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21001203211 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21001203191 and 21001203200.

It is not an unprimeable number, because it can be changed into a prime (21001203221) 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, 14809731 + ... + 14811148.

It is an arithmetic number, because the mean of its divisors is an integer number (5257706200).

Almost surely, 2^21001203211 is an apocalyptic number.

21001203211 is a deficient number, since it is larger than the sum of its proper divisors (29621589).

21001203211 is an equidigital number, since it uses as much as digits as its factorization.

21001203211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29621588.

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 21001203211 its reverse (11230210012), we get a palindrome (32231413223).

The spelling of 21001203211 in words is "twenty-one billion, one million, two hundred three thousand, two hundred eleven".