21254123 has 4 divisors (see below), whose sum is σ = 23186328. Its totient is φ = 19321920.

The previous prime is 21254119. The next prime is 21254143. The reversal of 21254123 is 32145212.

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 21254123 - 2² = 21254119 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a junction number, because it is equal to n+sod(n) for n = 21254095 and 21254104.

It is not an unprimeable number, because it can be changed into a prime (21254143) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 966086 + ... + 966107.

It is an arithmetic number, because the mean of its divisors is an integer number (5796582).

Almost surely, 2^21254123 is an apocalyptic number.

21254123 is a deficient number, since it is larger than the sum of its proper divisors (1932205).

21254123 is a wasteful number, since it uses less digits than its factorization.

21254123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1932204.

The product of its digits is 480, while the sum is 20.

The square root of 21254123 is about 4610.2194090954. The cubic root of 21254123 is about 277.0008254134. Note that the first 3 decimals are identical.

Adding to 21254123 its reverse (32145212), we get a palindrome (53399335).

The spelling of 21254123 in words is "twenty-one million, two hundred fifty-four thousand, one hundred twenty-three".