21432523 has 8 divisors (see below), whose sum is σ = 24541920. Its totient is φ = 18335040.

The previous prime is 21432493. The next prime is 21432539. The reversal of 21432523 is 32523412.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21432523 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 = 21432494 and 21432503.

It is not an unprimeable number, because it can be changed into a prime (21432553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1293 + ... + 6673.

It is an arithmetic number, because the mean of its divisors is an integer number (3067740).

Almost surely, 2^21432523 is an apocalyptic number.

21432523 is a deficient number, since it is larger than the sum of its proper divisors (3109397).

21432523 is an equidigital number, since it uses as much as digits as its factorization.

21432523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5957.

The product of its digits is 1440, while the sum is 22.

The square root of 21432523 is about 4629.5272976839. The cubic root of 21432523 is about 277.7736844849.

Adding to 21432523 its reverse (32523412), we get a palindrome (53955935).

The spelling of 21432523 in words is "twenty-one million, four hundred thirty-two thousand, five hundred twenty-three".