21221212101 has 16 divisors (see below), whose sum is σ = 29094441600. Its totient is φ = 13748643648.

The previous prime is 21221212079. The next prime is 21221212109. The reversal of 21221212101 is 10121212212.

It is not a de Polignac number, because 21221212101 - 2⁵ = 21221212069 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221212109) 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, 20806 + ... + 207063.

It is an arithmetic number, because the mean of its divisors is an integer number (1818402600).

Almost surely, 2^21221212101 is an apocalyptic number.

It is an amenable number.

21221212101 is a deficient number, since it is larger than the sum of its proper divisors (7873229499).

21221212101 is a wasteful number, since it uses less digits than its factorization.

21221212101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 228748.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21221212101 its reverse (10121212212), we get a palindrome (31342424313).

It can be divided in two parts, 21 and 221212101, that added together give a palindrome (221212122).

The spelling of 21221212101 in words is "twenty-one billion, two hundred twenty-one million, two hundred twelve thousand, one hundred one".