21101203123 has 32 divisors (see below), whose sum is σ = 28690421760. Its totient is φ = 14985509760.

The previous prime is 21101203111. The next prime is 21101203139. The reversal of 21101203123 is 32130210112.

It is not a de Polignac number, because 21101203123 - 2⁵ = 21101203091 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21101203097 and 21101203106.

It is not an unprimeable number, because it can be changed into a prime (21101203153) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 54340 + ... + 212497.

It is an arithmetic number, because the mean of its divisors is an integer number (896575680).

Almost surely, 2^21101203123 is an apocalyptic number.

21101203123 is a deficient number, since it is larger than the sum of its proper divisors (7589218637).

21101203123 is a wasteful number, since it uses less digits than its factorization.

21101203123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 266947.

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

Adding to 21101203123 its reverse (32130210112), we get a palindrome (53231413235).

The spelling of 21101203123 in words is "twenty-one billion, one hundred one million, two hundred three thousand, one hundred twenty-three".