21666576358783 has 2 divisors, whose sum is σ = 21666576358784. Its totient is φ = 21666576358782.

The previous prime is 21666576358727. The next prime is 21666576358811. The reversal of 21666576358783 is 38785367566612.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21666576358783 is a prime.

It is a super-2 number, since 2×21666576358783² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21666576358283) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10833288179391 + 10833288179392.

It is an arithmetic number, because the mean of its divisors is an integer number (10833288179392).

Almost surely, 2^{21666576358783} is an apocalyptic number.

21666576358783 is a deficient number, since it is larger than the sum of its proper divisors (1).

21666576358783 is an equidigital number, since it uses as much as digits as its factorization.

21666576358783 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1828915200, while the sum is 73.

The spelling of 21666576358783 in words is "twenty-one trillion, six hundred sixty-six billion, five hundred seventy-six million, three hundred fifty-eight thousand, seven hundred eighty-three".