21142285 has 4 divisors (see below), whose sum is σ = 25370748. Its totient is φ = 16913824.

The previous prime is 21142273. The next prime is 21142291. The reversal of 21142285 is 58224112.

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

It can be written as a sum of positive squares in 2 ways, for example, as 9108324 + 12033961 = 3018^2 + 3469^2 .

It is a cyclic number.

It is not a de Polignac number, because 21142285 - 2¹¹ = 21140237 is a prime.

It is a Duffinian number.

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, 2114224 + ... + 2114233.

It is an arithmetic number, because the mean of its divisors is an integer number (6342687).

Almost surely, 2^21142285 is an apocalyptic number.

It is an amenable number.

21142285 is a deficient number, since it is larger than the sum of its proper divisors (4228463).

21142285 is an equidigital number, since it uses as much as digits as its factorization.

21142285 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4228462.

The product of its digits is 1280, while the sum is 25.

The square root of 21142285 is about 4598.0740533402. The cubic root of 21142285 is about 276.5141164788.

Adding to 21142285 its reverse (58224112), we get a palindrome (79366397).

The spelling of 21142285 in words is "twenty-one million, one hundred forty-two thousand, two hundred eighty-five".