21438250 has 32 divisors (see below), whose sum is σ = 41530320. Its totient is φ = 8276800.

The previous prime is 21438239. The next prime is 21438253. The reversal of 21438250 is 5283412.

It can be written as a sum of positive squares in 8 ways, for example, as 10609 + 21427641 = 103^2 + 4629^2 .

It is a Harshad number since it is a multiple of its sum of digits (25).

It is not an unprimeable number, because it can be changed into a prime (21438253) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5772 + ... + 8728.

Almost surely, 2^21438250 is an apocalyptic number.

21438250 is a deficient number, since it is larger than the sum of its proper divisors (20092070).

21438250 is a wasteful number, since it uses less digits than its factorization.

21438250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3003 (or 2993 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 25.

The square root of 21438250 is about 4630.1457860417. The cubic root of 21438250 is about 277.7984236506.

The spelling of 21438250 in words is "twenty-one million, four hundred thirty-eight thousand, two hundred fifty".