21768323 has 2 divisors, whose sum is σ = 21768324. Its totient is φ = 21768322.

The previous prime is 21768289. The next prime is 21768337. The reversal of 21768323 is 32386712.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21768323 - 2¹² = 21764227 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21768323.

It is not a weakly prime, because it can be changed into another prime (21768343) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10884161 + 10884162.

It is an arithmetic number, because the mean of its divisors is an integer number (10884162).

Almost surely, 2^21768323 is an apocalyptic number.

21768323 is a deficient number, since it is larger than the sum of its proper divisors (1).

21768323 is an equidigital number, since it uses as much as digits as its factorization.

21768323 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12096, while the sum is 32.

The square root of 21768323 is about 4665.6535447888. The cubic root of 21768323 is about 279.2168720972.

The spelling of 21768323 in words is "twenty-one million, seven hundred sixty-eight thousand, three hundred twenty-three".