21281450 has 24 divisors (see below), whose sum is σ = 41913612. Its totient is φ = 8011520.

The previous prime is 21281441. The next prime is 21281453. The reversal of 21281450 is 5418212.

It can be written as a sum of positive squares in 6 ways, for example, as 10699441 + 10582009 = 3271^2 + 3253^2 .

It is a super-2 number, since 2×21281450² = 905800228205000, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21281453) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11669 + ... + 13368.

Almost surely, 2^21281450 is an apocalyptic number.

21281450 is a deficient number, since it is larger than the sum of its proper divisors (20632162).

21281450 is a wasteful number, since it uses less digits than its factorization.

21281450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25066 (or 25061 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 23.

The square root of 21281450 is about 4613.1821988731. The cubic root of 21281450 is about 277.1194903853.

Adding to 21281450 its reverse (5418212), we get a palindrome (26699662).

The spelling of 21281450 in words is "twenty-one million, two hundred eighty-one thousand, four hundred fifty".