20101231123 has 4 divisors (see below), whose sum is σ = 20101514688. Its totient is φ = 20100947560.

The previous prime is 20101231091. The next prime is 20101231159. The reversal of 20101231123 is 32113210102.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 32113210102 = 2 ⋅16056605051.

It is a cyclic number.

It is not a de Polignac number, because 20101231123 - 2⁵ = 20101231091 is a prime.

It is a super-2 number, since 2×20101231123² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20101231097 and 20101231106.

It is not an unprimeable number, because it can be changed into a prime (20101231723) 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, 69465 + ... + 212197.

It is an arithmetic number, because the mean of its divisors is an integer number (5025378672).

Almost surely, 2^20101231123 is an apocalyptic number.

20101231123 is a deficient number, since it is larger than the sum of its proper divisors (283565).

20101231123 is a wasteful number, since it uses less digits than its factorization.

20101231123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 283564.

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 20101231123 its reverse (32113210102), we get a palindrome (52214441225).

The spelling of 20101231123 in words is "twenty billion, one hundred one million, two hundred thirty-one thousand, one hundred twenty-three".