21260250 has 96 divisors (see below), whose sum is σ = 62786880. Its totient is φ = 5148000.

The previous prime is 21260233. The next prime is 21260273. The reversal of 21260250 is 5206212.

21260250 is a `hidden beast` number, since 2 + 12 + 602 + 50 = 666.

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

It is a Curzon number.

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 47 ways as a sum of consecutive naturals, for example, 24321 + ... + 25179.

It is an arithmetic number, because the mean of its divisors is an integer number (654030).

Almost surely, 2^21260250 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21260250, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31393440).

21260250 is an abundant number, since it is smaller than the sum of its proper divisors (41526630).

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

21260250 is a wasteful number, since it uses less digits than its factorization.

21260250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 893 (or 880 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21260250 is about 4610.8838632089. The cubic root of 21260250 is about 277.0274401867.

Adding to 21260250 its reverse (5206212), we get a palindrome (26466462).

The spelling of 21260250 in words is "twenty-one million, two hundred sixty thousand, two hundred fifty".