21318339 has 8 divisors (see below), whose sum is σ = 32485120. Its totient is φ = 12181896.

The previous prime is 21318337. The next prime is 21318343. The reversal of 21318339 is 93381312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21318339 - 2¹ = 21318337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21318337) 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 7 ways as a sum of consecutive naturals, for example, 507559 + ... + 507600.

It is an arithmetic number, because the mean of its divisors is an integer number (4060640).

Almost surely, 2^21318339 is an apocalyptic number.

21318339 is a deficient number, since it is larger than the sum of its proper divisors (11166781).

21318339 is a wasteful number, since it uses less digits than its factorization.

21318339 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1015169.

The product of its digits is 3888, while the sum is 30.

The square root of 21318339 is about 4617.1786840017. The cubic root of 21318339 is about 277.2795164479.

The spelling of 21318339 in words is "twenty-one million, three hundred eighteen thousand, three hundred thirty-nine".