21101120123 has 4 divisors (see below), whose sum is σ = 21235522320. Its totient is φ = 20966717928.

The previous prime is 21101120113. The next prime is 21101120153. The reversal of 21101120123 is 32102110112.

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

It is a cyclic number.

It is not a de Polignac number, because 21101120123 - 2⁶ = 21101120059 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21101120098 and 21101120107.

It is not an unprimeable number, because it can be changed into a prime (21101120113) 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, 67200863 + ... + 67201176.

It is an arithmetic number, because the mean of its divisors is an integer number (5308880580).

Almost surely, 2^21101120123 is an apocalyptic number.

21101120123 is a deficient number, since it is larger than the sum of its proper divisors (134402197).

21101120123 is a wasteful number, since it uses less digits than its factorization.

21101120123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134402196.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 21101120123 its reverse (32102110112), we get a palindrome (53203230235).

The spelling of 21101120123 in words is "twenty-one billion, one hundred one million, one hundred twenty thousand, one hundred twenty-three".