21132423 has 24 divisors (see below), whose sum is σ = 34306272. Its totient is φ = 12437568.

The previous prime is 21132383. The next prime is 21132481. The reversal of 21132423 is 32423112.

21132423 is a `hidden beast` number, since 211 + 32 + 423 = 666.

It is not a de Polignac number, because 21132423 - 2¹⁰ = 21131399 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21132396 and 21132405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21132493) 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 23 ways as a sum of consecutive naturals, for example, 1236 + ... + 6617.

It is an arithmetic number, because the mean of its divisors is an integer number (1429428).

Almost surely, 2^21132423 is an apocalyptic number.

21132423 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21132423 is a deficient number, since it is larger than the sum of its proper divisors (13173849).

21132423 is a wasteful number, since it uses less digits than its factorization.

21132423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7895 (or 7892 counting only the distinct ones).

The product of its digits is 288, while the sum is 18.

The square root of 21132423 is about 4597.0015227320. The cubic root of 21132423 is about 276.4711156657.

Adding to 21132423 its reverse (32423112), we get a palindrome (53555535).

The spelling of 21132423 in words is "twenty-one million, one hundred thirty-two thousand, four hundred twenty-three".