21255250 has 16 divisors (see below), whose sum is σ = 39790296. Its totient is φ = 8502000.

The previous prime is 21255239. The next prime is 21255257. The reversal of 21255250 is 5255212.

It can be written as a sum of positive squares in 4 ways, for example, as 4941729 + 16313521 = 2223^2 + 4039^2 .

It is not an unprimeable number, because it can be changed into a prime (21255257) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42261 + ... + 42760.

Almost surely, 2^21255250 is an apocalyptic number.

21255250 is a deficient number, since it is larger than the sum of its proper divisors (18535046).

21255250 is an equidigital number, since it uses as much as digits as its factorization.

21255250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85038 (or 85028 counting only the distinct ones).

The product of its (nonzero) digits is 1000, while the sum is 22.

The square root of 21255250 is about 4610.3416359311. The cubic root of 21255250 is about 277.0057213170.

It can be divided in two parts, 212552 and 50, that multiplied together give a square (10627600 = 3260²).

The spelling of 21255250 in words is "twenty-one million, two hundred fifty-five thousand, two hundred fifty".