21774666 has 8 divisors (see below), whose sum is σ = 43549344. Its totient is φ = 7258220.

The previous prime is 21774647. The next prime is 21774667. The reversal of 21774666 is 66647712.

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

21774666 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (21774667) 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, 1814550 + ... + 1814561.

It is an arithmetic number, because the mean of its divisors is an integer number (5443668).

Almost surely, 2^21774666 is an apocalyptic number.

21774666 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.

21774666 is a wasteful number, since it uses less digits than its factorization.

21774666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3629116.

The product of its digits is 84672, while the sum is 39.

The square root of 21774666 is about 4666.3332499940. Note that the first 3 decimals coincide. The cubic root of 21774666 is about 279.2439894920.

The spelling of 21774666 in words is "twenty-one million, seven hundred seventy-four thousand, six hundred sixty-six".