21032423 has 4 divisors (see below), whose sum is σ = 21056520. Its totient is φ = 21008328.

The previous prime is 21032399. The next prime is 21032437. The reversal of 21032423 is 32423012.

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 21032423 - 2¹² = 21028327 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21032483) 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, 10688 + ... + 12501.

It is an arithmetic number, because the mean of its divisors is an integer number (5264130).

Almost surely, 2^21032423 is an apocalyptic number.

21032423 is a deficient number, since it is larger than the sum of its proper divisors (24097).

21032423 is an equidigital number, since it uses as much as digits as its factorization.

21032423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24096.

The product of its (nonzero) digits is 288, while the sum is 17.

The square root of 21032423 is about 4586.1119698498. Note that the first 3 decimals coincide. The cubic root of 21032423 is about 276.0343328781.

Adding to 21032423 its reverse (32423012), we get a palindrome (53455435).

The spelling of 21032423 in words is "twenty-one million, thirty-two thousand, four hundred twenty-three".