21250535 has 4 divisors (see below), whose sum is σ = 25500648. Its totient is φ = 17000424.

The previous prime is 21250517. The next prime is 21250553. The reversal of 21250535 is 53505212.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21250517) and next prime (21250553).

It is a cyclic number.

It is not a de Polignac number, because 21250535 - 2⁸ = 21250279 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21250535.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 2125049 + ... + 2125058.

It is an arithmetic number, because the mean of its divisors is an integer number (6375162).

Almost surely, 2^21250535 is an apocalyptic number.

21250535 is a deficient number, since it is larger than the sum of its proper divisors (4250113).

21250535 is an equidigital number, since it uses as much as digits as its factorization.

21250535 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4250112.

The product of its (nonzero) digits is 1500, while the sum is 23.

The square root of 21250535 is about 4609.8302571787. The cubic root of 21250535 is about 276.9852373023.

Adding to 21250535 its reverse (53505212), we get a palindrome (74755747).

The spelling of 21250535 in words is "twenty-one million, two hundred fifty thousand, five hundred thirty-five".