21423432 has 16 divisors (see below), whose sum is σ = 53558640. Its totient is φ = 7141136.

The previous prime is 21423421. The next prime is 21423487. The reversal of 21423432 is 23432412.

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 21423399 and 21423408.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 446298 + ... + 446345.

It is an arithmetic number, because the mean of its divisors is an integer number (3347415).

Almost surely, 2^21423432 is an apocalyptic number.

It is an amenable number.

21423432 is an abundant number, since it is smaller than the sum of its proper divisors (32135208).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21423432 is a wasteful number, since it uses less digits than its factorization.

21423432 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 892652 (or 892648 counting only the distinct ones).

The product of its digits is 1152, while the sum is 21.

The square root of 21423432 is about 4628.5453438418. The cubic root of 21423432 is about 277.7344046531.

Adding to 21423432 its reverse (23432412), we get a palindrome (44855844).

The spelling of 21423432 in words is "twenty-one million, four hundred twenty-three thousand, four hundred thirty-two".