21452123 has 16 divisors (see below), whose sum is σ = 27910656. Its totient is φ = 15987840.

The previous prime is 21452111. The next prime is 21452131. The reversal of 21452123 is 32125412.

It is not a de Polignac number, because 21452123 - 2⁸ = 21451867 is a prime.

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

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21452095 and 21452104.

It is not an unprimeable number, because it can be changed into a prime (21452923) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4286 + ... + 7827.

It is an arithmetic number, because the mean of its divisors is an integer number (1744416).

Almost surely, 2^21452123 is an apocalyptic number.

21452123 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21452123 is a deficient number, since it is larger than the sum of its proper divisors (6458533).

21452123 is a wasteful number, since it uses less digits than its factorization.

21452123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12154.

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

The square root of 21452123 is about 4631.6436607321. The cubic root of 21452123 is about 277.8583331819.

Adding to 21452123 its reverse (32125412), we get a palindrome (53577535).

Subtracting 21452123 from its reverse (32125412), we obtain a square (10673289 = 3267²).

The spelling of 21452123 in words is "twenty-one million, four hundred fifty-two thousand, one hundred twenty-three".