21284413 has 4 divisors (see below), whose sum is σ = 21325788. Its totient is φ = 21243040.

The previous prime is 21284411. The next prime is 21284423. The reversal of 21284413 is 31448212.

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 15705369 + 5579044 = 3963^2 + 2362^2 .

It is a cyclic number.

It is not a de Polignac number, because 21284413 - 2¹ = 21284411 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21284411) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19906 + ... + 20947.

It is an arithmetic number, because the mean of its divisors is an integer number (5331447).

Almost surely, 2^21284413 is an apocalyptic number.

It is an amenable number.

21284413 is a deficient number, since it is larger than the sum of its proper divisors (41375).

21284413 is an equidigital number, since it uses as much as digits as its factorization.

21284413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41374.

The product of its digits is 1536, while the sum is 25.

The square root of 21284413 is about 4613.5033326096. The cubic root of 21284413 is about 277.1323508333.

The spelling of 21284413 in words is "twenty-one million, two hundred eighty-four thousand, four hundred thirteen".