21454523 has 4 divisors (see below), whose sum is σ = 21468480. Its totient is φ = 21440568.

The previous prime is 21454483. The next prime is 21454541. The reversal of 21454523 is 32545412.

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 21454523 - 2¹⁶ = 21388987 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 = 21454492 and 21454501.

It is not an unprimeable number, because it can be changed into a prime (21454123) 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, 4340 + ... + 7857.

It is an arithmetic number, because the mean of its divisors is an integer number (5367120).

Almost surely, 2^21454523 is an apocalyptic number.

21454523 is a deficient number, since it is larger than the sum of its proper divisors (13957).

21454523 is a wasteful number, since it uses less digits than its factorization.

21454523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13956.

The product of its digits is 4800, while the sum is 26.

The square root of 21454523 is about 4631.9027407751. The cubic root of 21454523 is about 277.8686947847.

Adding to 21454523 its reverse (32545412), we get a palindrome (53999935).

The spelling of 21454523 in words is "twenty-one million, four hundred fifty-four thousand, five hundred twenty-three".