21660222 has 8 divisors (see below), whose sum is σ = 43320456. Its totient is φ = 7220072.

The previous prime is 21660211. The next prime is 21660239. The reversal of 21660222 is 22206612.

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

21660222 is an admirable number.

It is a congruent number.

It is an unprimeable number.

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, 1805013 + ... + 1805024.

It is an arithmetic number, because the mean of its divisors is an integer number (5415057).

Almost surely, 2^21660222 is an apocalyptic number.

21660222 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21660222 is a wasteful number, since it uses less digits than its factorization.

21660222 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3610042.

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 21660222 is about 4654.0543615218. The cubic root of 21660222 is about 278.7539100043.

Adding to 21660222 its reverse (22206612), we get a palindrome (43866834).

The spelling of 21660222 in words is "twenty-one million, six hundred sixty thousand, two hundred twenty-two".