21003250 has 32 divisors (see below), whose sum is σ = 40687920. Its totient is φ = 8108800.

The previous prime is 21003247. The next prime is 21003259. The reversal of 21003250 is 5230012.

It can be written as a sum of positive squares in 8 ways, for example, as 17689 + 20985561 = 133^2 + 4581^2 .

It is a super-2 number, since 2×21003250² = 882273021125000, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21003250.

It is not an unprimeable number, because it can be changed into a prime (21003259) 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, 5802 + ... + 8698.

Almost surely, 2^21003250 is an apocalyptic number.

21003250 is a deficient number, since it is larger than the sum of its proper divisors (19684670).

21003250 is a wasteful number, since it uses less digits than its factorization.

21003250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2943 (or 2933 counting only the distinct ones).

The product of its (nonzero) digits is 60, while the sum is 13.

The square root of 21003250 is about 4582.9302853087. The cubic root of 21003250 is about 275.9066494493.

Adding to 21003250 its reverse (5230012), we get a palindrome (26233262).

The spelling of 21003250 in words is "twenty-one million, three thousand, two hundred fifty".