21250504 has 48 divisors (see below), whose sum is σ = 45366300. Its totient is φ = 9313920.

The previous prime is 21250499. The next prime is 21250511. The reversal of 21250504 is 40505212.

It can be written as a sum of positive squares in 2 ways, for example, as 21141604 + 108900 = 4598^2 + 330^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 27694 + ... + 28450.

Almost surely, 2^21250504 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21250504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22683150).

21250504 is an abundant number, since it is smaller than the sum of its proper divisors (24115796).

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

21250504 is a wasteful number, since it uses less digits than its factorization.

21250504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 814 (or 799 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 19.

The square root of 21250504 is about 4609.8268947977. The cubic root of 21250504 is about 276.9851026147.

Adding to 21250504 its reverse (40505212), we get a palindrome (61755716).

The spelling of 21250504 in words is "twenty-one million, two hundred fifty thousand, five hundred four".