Adding to 21234545 its reverse (54543212), we get a palindrome (75777757).
It is a happy number.
21234545 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.
It is a sphenic number, since it is the product of 3 distinct primes.
It is a cyclic number.
It is an alternating number because its digits alternate between even and odd.
It is a Duffinian number.
Almost surely, 221234545 is an apocalyptic number.
It is an amenable number.
21234545 is a wasteful number, since it uses less digits than its factorization.
21234545 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 4999.
The square root of 21234545 is about 4608.0955936265. The cubic root of 21234545 is about 276.9157472043.
The spelling of 21234545 in words is "twenty-one million, two hundred thirty-four thousand, five hundred forty-five".