21116250 has 60 divisors (see below), whose sum is σ = 57202002. Its totient is φ = 5628000.

The previous prime is 21116219. The next prime is 21116257. The reversal of 21116250 is 5261112.

It can be written as a sum of positive squares in 5 ways, for example, as 622521 + 20493729 = 789^2 + 4527^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21116257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 10312 + ... + 12188.

Almost surely, 2^21116250 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21116250, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28601001).

21116250 is an abundant number, since it is smaller than the sum of its proper divisors (36085752).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21116250 is a wasteful number, since it uses less digits than its factorization.

21116250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1905 (or 1887 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

The square root of 21116250 is about 4595.2421046121. The cubic root of 21116250 is about 276.4005683286.

Adding to 21116250 its reverse (5261112), we get a palindrome (26377362).

It can be divided in two parts, 211 and 16250, that added together give a palindrome (16461).

The spelling of 21116250 in words is "twenty-one million, one hundred sixteen thousand, two hundred fifty".