21166339 has 4 divisors (see below), whose sum is σ = 21215656. Its totient is φ = 21117024.

The previous prime is 21166337. The next prime is 21166357. The reversal of 21166339 is 93366112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21166339 - 2¹ = 21166337 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21166339.

It is not an unprimeable number, because it can be changed into a prime (21166337) 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, 24009 + ... + 24874.

It is an arithmetic number, because the mean of its divisors is an integer number (5303914).

Almost surely, 2^21166339 is an apocalyptic number.

21166339 is a deficient number, since it is larger than the sum of its proper divisors (49317).

21166339 is an equidigital number, since it uses as much as digits as its factorization.

21166339 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49316.

The product of its digits is 5832, while the sum is 31.

The square root of 21166339 is about 4600.6889701435. The cubic root of 21166339 is about 276.6189419462.

The spelling of 21166339 in words is "twenty-one million, one hundred sixty-six thousand, three hundred thirty-nine".