21415285 has 4 divisors (see below), whose sum is σ = 25698348. Its totient is φ = 17132224.

The previous prime is 21415249. The next prime is 21415307. The reversal of 21415285 is 58251412.

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 6345361 + 15069924 = 2519^2 + 3882^2 .

It is a cyclic number.

It is not a de Polignac number, because 21415285 - 2¹³ = 21407093 is a prime.

It is a super-2 number, since 2×21415285² = 917228863262450, which contains 22 as substring.

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 (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2141524 + ... + 2141533.

It is an arithmetic number, because the mean of its divisors is an integer number (6424587).

Almost surely, 2^21415285 is an apocalyptic number.

It is an amenable number.

21415285 is a deficient number, since it is larger than the sum of its proper divisors (4283063).

21415285 is an equidigital number, since it uses as much as digits as its factorization.

21415285 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4283062.

The product of its digits is 3200, while the sum is 28.

The square root of 21415285 is about 4627.6651780352. The cubic root of 21415285 is about 277.6991941559.

Adding to 21415285 its reverse (58251412), we get a palindrome (79666697).

The spelling of 21415285 in words is "twenty-one million, four hundred fifteen thousand, two hundred eighty-five".