21774647 has 2 divisors, whose sum is σ = 21774648. Its totient is φ = 21774646.

The previous prime is 21774631. The next prime is 21774667. The reversal of 21774647 is 74647712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21774647 - 2⁴ = 21774631 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21774647.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21774667) 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 as a sum of consecutive naturals, namely, 10887323 + 10887324.

It is an arithmetic number, because the mean of its divisors is an integer number (10887324).

Almost surely, 2^21774647 is an apocalyptic number.

21774647 is a deficient number, since it is larger than the sum of its proper divisors (1).

21774647 is an equidigital number, since it uses as much as digits as its factorization.

21774647 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 65856, while the sum is 38.

The square root of 21774647 is about 4666.3312141339. The cubic root of 21774647 is about 279.2439082716.

The spelling of 21774647 in words is "twenty-one million, seven hundred seventy-four thousand, six hundred forty-seven".