21121250 has 40 divisors (see below), whose sum is σ = 40383948. Its totient is φ = 8280000.

The previous prime is 21121249. The next prime is 21121253. The reversal of 21121250 is 5212112.

It can be written as a sum of positive squares in 10 ways, for example, as 10118761 + 11002489 = 3181^2 + 3317^2 .

It is a super-2 number, since 2×21121250² = 892214403125000, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21121253) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 76112 + ... + 76388.

Almost surely, 2^21121250 is an apocalyptic number.

21121250 is a deficient number, since it is larger than the sum of its proper divisors (19262698).

21121250 is an equidigital number, since it uses as much as digits as its factorization.

21121250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 360 (or 345 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 14.

The square root of 21121250 is about 4595.7861133869. The cubic root of 21121250 is about 276.4223823940.

Adding to 21121250 its reverse (5212112), we get a palindrome (26333362).

The spelling of 21121250 in words is "twenty-one million, one hundred twenty-one thousand, two hundred fifty".