21012101211 has 4 divisors (see below), whose sum is σ = 28016134952. Its totient is φ = 14008067472.

The previous prime is 21012101093. The next prime is 21012101251. The reversal of 21012101211 is 11210121012.

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

It is not a de Polignac number, because 21012101211 - 2¹⁸ = 21011839067 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21012101251) 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, 3502016866 + ... + 3502016871.

It is an arithmetic number, because the mean of its divisors is an integer number (7004033738).

Almost surely, 2^21012101211 is an apocalyptic number.

21012101211 is a deficient number, since it is larger than the sum of its proper divisors (7004033741).

21012101211 is an equidigital number, since it uses as much as digits as its factorization.

21012101211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7004033740.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21012101211 its reverse (11210121012), we get a palindrome (32222222223).

It can be divided in two parts, 210121012 and 11, that multiplied together give a palindrome (2311331132).

The spelling of 21012101211 in words is "twenty-one billion, twelve million, one hundred one thousand, two hundred eleven".