21780766199 has 2 divisors, whose sum is σ = 21780766200. Its totient is φ = 21780766198.

The previous prime is 21780766193. The next prime is 21780766213. The reversal of 21780766199 is 99166708712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21780766199 - 2¹⁶ = 21780700663 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21780766193) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10890383099 + 10890383100.

It is an arithmetic number, because the mean of its divisors is an integer number (10890383100).

Almost surely, 2^21780766199 is an apocalyptic number.

21780766199 is a deficient number, since it is larger than the sum of its proper divisors (1).

21780766199 is an equidigital number, since it uses as much as digits as its factorization.

21780766199 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2286144, while the sum is 56.

The spelling of 21780766199 in words is "twenty-one billion, seven hundred eighty million, seven hundred sixty-six thousand, one hundred ninety-nine".