21354123 has 16 divisors (see below), whose sum is σ = 32739840. Its totient is φ = 12127296.

The previous prime is 21354107. The next prime is 21354139. The reversal of 21354123 is 32145312.

It is an interprime number because it is at equal distance from previous prime (21354107) and next prime (21354139).

It is not a de Polignac number, because 21354123 - 2⁴ = 21354107 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a plaindrome in base 13.

It is a self number, because there is not a number n which added to its sum of digits gives 21354123.

It is not an unprimeable number, because it can be changed into a prime (21354103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 463 + ... + 6551.

It is an arithmetic number, because the mean of its divisors is an integer number (2046240).

Almost surely, 2^21354123 is an apocalyptic number.

21354123 is a deficient number, since it is larger than the sum of its proper divisors (11385717).

21354123 is a wasteful number, since it uses less digits than its factorization.

21354123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6266.

The product of its digits is 720, while the sum is 21.

The square root of 21354123 is about 4621.0521529193. The cubic root of 21354123 is about 277.4345726768.

Adding to 21354123 its reverse (32145312), we get a palindrome (53499435).

The spelling of 21354123 in words is "twenty-one million, three hundred fifty-four thousand, one hundred twenty-three".