21086250 has 40 divisors (see below), whose sum is σ = 52708128. Its totient is φ = 5622000.

The previous prime is 21086249. The next prime is 21086251. The reversal of 21086250 is 5268012.

It is an interprime number because it is at equal distance from previous prime (21086249) and next prime (21086251).

It is a self number, because there is not a number n which added to its sum of digits gives 21086250.

It is not an unprimeable number, because it can be changed into a prime (21086251) 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, 939 + ... + 6561.

Almost surely, 2^21086250 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21086250, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26354064).

21086250 is an abundant number, since it is smaller than the sum of its proper divisors (31621878).

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

21086250 is an equidigital number, since it uses as much as digits as its factorization.

21086250 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5648 (or 5633 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 21086250 is about 4591.9766985472. The cubic root of 21086250 is about 276.2696115695.

The spelling of 21086250 in words is "twenty-one million, eighty-six thousand, two hundred fifty".