21771366 has 8 divisors (see below), whose sum is σ = 43542744. Its totient is φ = 7257120.

The previous prime is 21771361. The next prime is 21771367. The reversal of 21771366 is 66317712.

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

21771366 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21771361) 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, 1814275 + ... + 1814286.

It is an arithmetic number, because the mean of its divisors is an integer number (5442843).

Almost surely, 2^21771366 is an apocalyptic number.

21771366 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.

21771366 is a wasteful number, since it uses less digits than its factorization.

21771366 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3628566.

The product of its digits is 10584, while the sum is 33.

The square root of 21771366 is about 4665.9796399041. The cubic root of 21771366 is about 279.2298820927.

The spelling of 21771366 in words is "twenty-one million, seven hundred seventy-one thousand, three hundred sixty-six".