21126250 has 20 divisors (see below), whose sum is σ = 39601386. Its totient is φ = 8450000.

The previous prime is 21126229. The next prime is 21126253. The reversal of 21126250 is 5262112.

It can be written as a sum of positive squares in 5 ways, for example, as 4748041 + 16378209 = 2179^2 + 4047^2 .

It is not an unprimeable number, because it can be changed into a prime (21126253) by changing a digit.

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 9 ways as a sum of consecutive naturals, for example, 7201 + ... + 9700.

Almost surely, 2^21126250 is an apocalyptic number.

21126250 is a deficient number, since it is larger than the sum of its proper divisors (18475136).

21126250 is an equidigital number, since it uses as much as digits as its factorization.

21126250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16923 (or 16908 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 21126250 is about 4596.3300577744. The cubic root of 21126250 is about 276.4441930170. Note that the first 3 decimals are identical.

Adding to 21126250 its reverse (5262112), we get a palindrome (26388362).

The spelling of 21126250 in words is "twenty-one million, one hundred twenty-six thousand, two hundred fifty".