21010110121 has 32 divisors (see below), whose sum is σ = 28311591168. Its totient is φ = 15057411840.

The previous prime is 21010110113. The next prime is 21010110133. The reversal of 21010110121 is 12101101012.

It is a cyclic number.

It is not a de Polignac number, because 21010110121 - 2³ = 21010110113 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21010110098 and 21010110107.

It is not an unprimeable number, because it can be changed into a prime (21010110101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 239391 + ... + 315163.

It is an arithmetic number, because the mean of its divisors is an integer number (884737224).

Almost surely, 2^21010110121 is an apocalyptic number.

It is an amenable number.

21010110121 is a deficient number, since it is larger than the sum of its proper divisors (7301481047).

21010110121 is a wasteful number, since it uses less digits than its factorization.

21010110121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76081.

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

Adding to 21010110121 its reverse (12101101012), we get a palindrome (33111211133).

It can be divided in two parts, 21010 and 110121, that added together give a palindrome (131131).

The spelling of 21010110121 in words is "twenty-one billion, ten million, one hundred ten thousand, one hundred twenty-one".