21284337 has 4 divisors (see below), whose sum is σ = 28379120. Its totient is φ = 14189556.

The previous prime is 21284299. The next prime is 21284339. The reversal of 21284337 is 73348212.

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 21284337 - 2⁶ = 21284273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21284339) 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, 3547387 + ... + 3547392.

It is an arithmetic number, because the mean of its divisors is an integer number (7094780).

Almost surely, 2^21284337 is an apocalyptic number.

It is an amenable number.

21284337 is a deficient number, since it is larger than the sum of its proper divisors (7094783).

21284337 is an equidigital number, since it uses as much as digits as its factorization.

21284337 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7094782.

The product of its digits is 8064, while the sum is 30.

The square root of 21284337 is about 4613.4950959116. The cubic root of 21284337 is about 277.1320209819.

The spelling of 21284337 in words is "twenty-one million, two hundred eighty-four thousand, three hundred thirty-seven".