21947116492811 has 2 divisors, whose sum is σ = 21947116492812. Its totient is φ = 21947116492810.

The previous prime is 21947116492781. The next prime is 21947116492867. The reversal of 21947116492811 is 11829461174912.

It is a happy number.

It is an a-pointer prime, because the next prime (21947116492867) can be obtained adding 21947116492811 to its sum of digits (56).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21947116492811 - 2¹⁴ = 21947116476427 is a prime.

It is not a weakly prime, because it can be changed into another prime (21947119492811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10973558246405 + 10973558246406.

It is an arithmetic number, because the mean of its divisors is an integer number (10973558246406).

Almost surely, 2^{21947116492811} is an apocalyptic number.

21947116492811 is a deficient number, since it is larger than the sum of its proper divisors (1).

21947116492811 is an equidigital number, since it uses as much as digits as its factorization.

21947116492811 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1741824, while the sum is 56.

The spelling of 21947116492811 in words is "twenty-one trillion, nine hundred forty-seven billion, one hundred sixteen million, four hundred ninety-two thousand, eight hundred eleven".