21764783 has 2 divisors, whose sum is σ = 21764784. Its totient is φ = 21764782.

The previous prime is 21764773. The next prime is 21764791. The reversal of 21764783 is 38746712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21764783 - 2¹⁴ = 21748399 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21764723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10882391 + 10882392.

It is an arithmetic number, because the mean of its divisors is an integer number (10882392).

Almost surely, 2^21764783 is an apocalyptic number.

21764783 is a deficient number, since it is larger than the sum of its proper divisors (1).

21764783 is an equidigital number, since it uses as much as digits as its factorization.

21764783 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 56448, while the sum is 38.

The square root of 21764783 is about 4665.2741612900. The cubic root of 21764783 is about 279.2017357098.

The spelling of 21764783 in words is "twenty-one million, seven hundred sixty-four thousand, seven hundred eighty-three".