21454445 has 4 divisors (see below), whose sum is σ = 25745340. Its totient is φ = 17163552.

The previous prime is 21454441. The next prime is 21454483. The reversal of 21454445 is 54445412.

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 4791721 + 16662724 = 2189^2 + 4082^2 .

It is a cyclic number.

It is not a de Polignac number, because 21454445 - 2² = 21454441 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21454441) 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, 2145440 + ... + 2145449.

It is an arithmetic number, because the mean of its divisors is an integer number (6436335).

Almost surely, 2^21454445 is an apocalyptic number.

It is an amenable number.

21454445 is a deficient number, since it is larger than the sum of its proper divisors (4290895).

21454445 is an equidigital number, since it uses as much as digits as its factorization.

21454445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4290894.

The product of its digits is 12800, while the sum is 29.

The square root of 21454445 is about 4631.8943209015. The cubic root of 21454445 is about 277.8683580447.

Adding to 21454445 its reverse (54445412), we get a palindrome (75899857).

The spelling of 21454445 in words is "twenty-one million, four hundred fifty-four thousand, four hundred forty-five".