21666346624211 has 2 divisors, whose sum is σ = 21666346624212. Its totient is φ = 21666346624210.

The previous prime is 21666346624163. The next prime is 21666346624229. The reversal of 21666346624211 is 11242664366612.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21666346624211 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21666346624211.

It is not a weakly prime, because it can be changed into another prime (21666346624271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10833173312105 + 10833173312106.

It is an arithmetic number, because the mean of its divisors is an integer number (10833173312106).

Almost surely, 2^{21666346624211} is an apocalyptic number.

21666346624211 is a deficient number, since it is larger than the sum of its proper divisors (1).

21666346624211 is an equidigital number, since it uses as much as digits as its factorization.

21666346624211 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2985984, while the sum is 50.

The spelling of 21666346624211 in words is "twenty-one trillion, six hundred sixty-six billion, three hundred forty-six million, six hundred twenty-four thousand, two hundred eleven".