21211010101 has 4 divisors (see below), whose sum is σ = 21421020204. Its totient is φ = 21001000000.

The previous prime is 21211010099. The next prime is 21211010129. The reversal of 21211010101 is 10101011212.

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

It can be written as a sum of positive squares in 2 ways, for example, as 16128746001 + 5082264100 = 126999^2 + 71290^2 .

It is a cyclic number.

It is not a de Polignac number, because 21211010101 - 2¹ = 21211010099 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211010131) 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, 105004900 + ... + 105005101.

It is an arithmetic number, because the mean of its divisors is an integer number (5355255051).

Almost surely, 2^21211010101 is an apocalyptic number.

It is an amenable number.

21211010101 is a deficient number, since it is larger than the sum of its proper divisors (210010103).

21211010101 is a wasteful number, since it uses less digits than its factorization.

21211010101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210010102.

The product of its (nonzero) digits is 4, while the sum is 10.

Adding to 21211010101 its reverse (10101011212), we get a palindrome (31312021313).

The spelling of 21211010101 in words is "twenty-one billion, two hundred eleven million, ten thousand, one hundred one".