21001213211 has 16 divisors (see below), whose sum is σ = 24262672608. Its totient is φ = 17965555200.

The previous prime is 21001213193. The next prime is 21001213217. The reversal of 21001213211 is 11231210012.

It is a cyclic number.

It is not a de Polignac number, because 21001213211 - 2⁶ = 21001213147 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21001213217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1859321 + ... + 1870581.

It is an arithmetic number, because the mean of its divisors is an integer number (1516417038).

Almost surely, 2^21001213211 is an apocalyptic number.

21001213211 is a deficient number, since it is larger than the sum of its proper divisors (3261459397).

21001213211 is a wasteful number, since it uses less digits than its factorization.

21001213211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21262.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 21001213211 its reverse (11231210012), we get a palindrome (32232423223).

The spelling of 21001213211 in words is "twenty-one billion, one million, two hundred thirteen thousand, two hundred eleven".