21331250 has 24 divisors (see below), whose sum is σ = 40005252. Its totient is φ = 8530000.

The previous prime is 21331217. The next prime is 21331267. The reversal of 21331250 is 5213312.

It can be written as a sum of positive squares in 6 ways, for example, as 143641 + 21187609 = 379^2 + 4603^2 .

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 4544 + ... + 7956.

Almost surely, 2^21331250 is an apocalyptic number.

21331250 is a deficient number, since it is larger than the sum of its proper divisors (18674002).

21331250 is an frugal number, since it uses more digits than its factorization.

21331250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3440 (or 3420 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 17.

The square root of 21331250 is about 4618.5766205618. The cubic root of 21331250 is about 277.3354813048.

Adding to 21331250 its reverse (5213312), we get a palindrome (26544562).

The spelling of 21331250 in words is "twenty-one million, three hundred thirty-one thousand, two hundred fifty".