21010110123 has 4 divisors (see below), whose sum is σ = 28013480168. Its totient is φ = 14006740080.

The previous prime is 21010110113. The next prime is 21010110133. The reversal of 21010110123 is 32101101012.

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

It is an interprime number because it is at equal distance from previous prime (21010110113) and next prime (21010110133).

It is not a de Polignac number, because 21010110123 - 2⁹ = 21010109611 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21010110099 and 21010110108.

It is not an unprimeable number, because it can be changed into a prime (21010110113) 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, 3501685018 + ... + 3501685023.

It is an arithmetic number, because the mean of its divisors is an integer number (7003370042).

Almost surely, 2^21010110123 is an apocalyptic number.

21010110123 is a deficient number, since it is larger than the sum of its proper divisors (7003370045).

21010110123 is an equidigital number, since it uses as much as digits as its factorization.

21010110123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7003370044.

The product of its (nonzero) digits is 12, while the sum is 12.

Adding to 21010110123 its reverse (32101101012), we get a palindrome (53111211135).

The spelling of 21010110123 in words is "twenty-one billion, ten million, one hundred ten thousand, one hundred twenty-three".