21284013 has 4 divisors (see below), whose sum is σ = 28378688. Its totient is φ = 14189340.

The previous prime is 21283987. The next prime is 21284041. The reversal of 21284013 is 31048212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21284013 - 2⁹ = 21283501 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 (21284093) by changing a digit.

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, 3547333 + ... + 3547338.

It is an arithmetic number, because the mean of its divisors is an integer number (7094672).

Almost surely, 2^21284013 is an apocalyptic number.

It is an amenable number.

21284013 is a deficient number, since it is larger than the sum of its proper divisors (7094675).

21284013 is an equidigital number, since it uses as much as digits as its factorization.

21284013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7094674.

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 21284013 is about 4613.4599814022. The cubic root of 21284013 is about 277.1306147642.

The spelling of 21284013 in words is "twenty-one million, two hundred eighty-four thousand, thirteen".