21234305123 has 4 divisors (see below), whose sum is σ = 21235494288. Its totient is φ = 21233115960.

The previous prime is 21234305101. The next prime is 21234305129. The reversal of 21234305123 is 32150343212.

It is a happy number.

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 21234305123 - 2³⁴ = 4054435939 is a prime.

It is a super-3 number, since 3×21234305123³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21234305092 and 21234305101.

It is not an unprimeable number, because it can be changed into a prime (21234305129) 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, 567383 + ... + 603648.

It is an arithmetic number, because the mean of its divisors is an integer number (5308873572).

Almost surely, 2^21234305123 is an apocalyptic number.

21234305123 is a deficient number, since it is larger than the sum of its proper divisors (1189165).

21234305123 is a wasteful number, since it uses less digits than its factorization.

21234305123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1189164.

The product of its (nonzero) digits is 4320, while the sum is 26.

Adding to 21234305123 its reverse (32150343212), we get a palindrome (53384648335).

The spelling of 21234305123 in words is "twenty-one billion, two hundred thirty-four million, three hundred five thousand, one hundred twenty-three".