21916766 has 8 divisors (see below), whose sum is σ = 34605480. Its totient is φ = 10381608.

The previous prime is 21916759. The next prime is 21916793. The reversal of 21916766 is 66761912.

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

It is a Harshad number since it is a multiple of its sum of digits (38), and also a Moran number because the ratio is a prime number: 576757 = 21916766 / (2 + 1 + 9 + 1 + 6 + 7 + 6 + 6).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 288341 + ... + 288416.

It is an arithmetic number, because the mean of its divisors is an integer number (4325685).

Almost surely, 2^21916766 is an apocalyptic number.

21916766 is a deficient number, since it is larger than the sum of its proper divisors (12688714).

21916766 is a wasteful number, since it uses less digits than its factorization.

21916766 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 576778.

The product of its digits is 27216, while the sum is 38.

The square root of 21916766 is about 4681.5345774650. The cubic root of 21916766 is about 279.8501153590.

The spelling of 21916766 in words is "twenty-one million, nine hundred sixteen thousand, seven hundred sixty-six".