21432445 has 4 divisors (see below), whose sum is σ = 25718940. Its totient is φ = 17145952.

The previous prime is 21432443. The next prime is 21432473. The reversal of 21432445 is 54423412.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10582009 + 10850436 = 3253^2 + 3294^2 .

It is a cyclic number.

It is not a de Polignac number, because 21432445 - 2¹ = 21432443 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21432443) 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, 2143240 + ... + 2143249.

It is an arithmetic number, because the mean of its divisors is an integer number (6429735).

Almost surely, 2^21432445 is an apocalyptic number.

It is an amenable number.

21432445 is a deficient number, since it is larger than the sum of its proper divisors (4286495).

21432445 is an equidigital number, since it uses as much as digits as its factorization.

21432445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4286494.

The product of its digits is 3840, while the sum is 25.

The square root of 21432445 is about 4629.5188734900. The cubic root of 21432445 is about 277.7733475145.

Adding to 21432445 its reverse (54423412), we get a palindrome (75855857).

It can be divided in two parts, 214324 and 45, that added together give a square (214369 = 463²).

The spelling of 21432445 in words is "twenty-one million, four hundred thirty-two thousand, four hundred forty-five".