21316783 has 2 divisors, whose sum is σ = 21316784. Its totient is φ = 21316782.

The previous prime is 21316753. The next prime is 21316819. The reversal of 21316783 is 38761312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21316783 - 2⁵ = 21316751 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21316723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10658391 + 10658392.

It is an arithmetic number, because the mean of its divisors is an integer number (10658392).

Almost surely, 2^21316783 is an apocalyptic number.

21316783 is a deficient number, since it is larger than the sum of its proper divisors (1).

21316783 is an equidigital number, since it uses as much as digits as its factorization.

21316783 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6048, while the sum is 31.

The square root of 21316783 is about 4617.0101797592. The cubic root of 21316783 is about 277.2727701840.

The spelling of 21316783 in words is "twenty-one million, three hundred sixteen thousand, seven hundred eighty-three".