21212221101 has 16 divisors (see below), whose sum is σ = 29276104704. Its totient is φ = 13650928704.

The previous prime is 21212221061. The next prime is 21212221117. The reversal of 21212221101 is 10112221212.

It is not a de Polignac number, because 21212221101 - 2¹⁰ = 21212220077 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212221601) 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, 738270 + ... + 766463.

It is an arithmetic number, because the mean of its divisors is an integer number (1829756544).

Almost surely, 2^21212221101 is an apocalyptic number.

It is an amenable number.

21212221101 is a deficient number, since it is larger than the sum of its proper divisors (8063883603).

21212221101 is a wasteful number, since it uses less digits than its factorization.

21212221101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1504900.

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

Adding to 21212221101 its reverse (10112221212), we get a palindrome (31324442313).

It can be divided in two parts, 2121 and 2221101, that added together give a palindrome (2223222).

The spelling of 21212221101 in words is "twenty-one billion, two hundred twelve million, two hundred twenty-one thousand, one hundred one".