21838766 has 4 divisors (see below), whose sum is σ = 32758152. Its totient is φ = 10919382.

The previous prime is 21838763. The next prime is 21838801. The reversal of 21838766 is 66783812.

It is a happy number.

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

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21838763) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5459690 + ... + 5459693.

It is an arithmetic number, because the mean of its divisors is an integer number (8189538).

Almost surely, 2^21838766 is an apocalyptic number.

21838766 is a deficient number, since it is larger than the sum of its proper divisors (10919386).

21838766 is a wasteful number, since it uses less digits than its factorization.

21838766 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10919385.

The product of its digits is 96768, while the sum is 41.

The square root of 21838766 is about 4673.1965505423. The cubic root of 21838766 is about 279.5177327531.

The spelling of 21838766 in words is "twenty-one million, eight hundred thirty-eight thousand, seven hundred sixty-six".