21304123 has 8 divisors (see below), whose sum is σ = 21585920. Its totient is φ = 21024360.

The previous prime is 21304121. The next prime is 21304139. The reversal of 21304123 is 32140312.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21304123 - 2¹ = 21304121 is a prime.

It is a super-3 number, since 3×21304123³ (a number of 23 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 = 21304097 and 21304106.

It is not an unprimeable number, because it can be changed into a prime (21304121) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34108 + ... + 34726.

It is an arithmetic number, because the mean of its divisors is an integer number (2698240).

Almost surely, 2^21304123 is an apocalyptic number.

21304123 is a deficient number, since it is larger than the sum of its proper divisors (281797).

21304123 is a wasteful number, since it uses less digits than its factorization.

21304123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1017.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 21304123 is about 4615.6389590175. The cubic root of 21304123 is about 277.2178687101.

Adding to 21304123 its reverse (32140312), we get a palindrome (53444435).

The spelling of 21304123 in words is "twenty-one million, three hundred four thousand, one hundred twenty-three".