21010403123 has 4 divisors (see below), whose sum is σ = 21196336008. Its totient is φ = 20824470240.

The previous prime is 21010403119. The next prime is 21010403231. The reversal of 21010403123 is 32130401012.

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 21010403123 - 2² = 21010403119 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21010403023) 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 3 ways as a sum of consecutive naturals, for example, 92966273 + ... + 92966498.

It is an arithmetic number, because the mean of its divisors is an integer number (5299084002).

Almost surely, 2^21010403123 is an apocalyptic number.

21010403123 is a deficient number, since it is larger than the sum of its proper divisors (185932885).

21010403123 is a wasteful number, since it uses less digits than its factorization.

21010403123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185932884.

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 21010403123 its reverse (32130401012), we get a palindrome (53140804135).

The spelling of 21010403123 in words is "twenty-one billion, ten million, four hundred three thousand, one hundred twenty-three".