21231020101 has 2 divisors, whose sum is σ = 21231020102. Its totient is φ = 21231020100.

The previous prime is 21231020087. The next prime is 21231020117. The reversal of 21231020101 is 10102013212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21213631201 + 17388900 = 145649^2 + 4170^2 .

It is a cyclic number.

It is not a de Polignac number, because 21231020101 - 2¹⁵ = 21230987333 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21231020131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10615510050 + 10615510051.

It is an arithmetic number, because the mean of its divisors is an integer number (10615510051).

Almost surely, 2^21231020101 is an apocalyptic number.

It is an amenable number.

21231020101 is a deficient number, since it is larger than the sum of its proper divisors (1).

21231020101 is an equidigital number, since it uses as much as digits as its factorization.

21231020101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 21231020101 its reverse (10102013212), we get a palindrome (31333033313).

The spelling of 21231020101 in words is "twenty-one billion, two hundred thirty-one million, twenty thousand, one hundred one".