21183691079861 has 2 divisors, whose sum is σ = 21183691079862. Its totient is φ = 21183691079860.

The previous prime is 21183691079821. The next prime is 21183691079891. The reversal of 21183691079861 is 16897019638112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15227406777361 + 5956284302500 = 3902231^2 + 2440550^2 .

It is a cyclic number.

It is not a de Polignac number, because 21183691079861 - 2¹⁴ = 21183691063477 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21183691079794 and 21183691079803.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21183691079821) 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, 10591845539930 + 10591845539931.

It is an arithmetic number, because the mean of its divisors is an integer number (10591845539931).

Almost surely, 2^{21183691079861} is an apocalyptic number.

It is an amenable number.

21183691079861 is a deficient number, since it is larger than the sum of its proper divisors (1).

21183691079861 is an equidigital number, since it uses as much as digits as its factorization.

21183691079861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7838208, while the sum is 62.

The spelling of 21183691079861 in words is "twenty-one trillion, one hundred eighty-three billion, six hundred ninety-one million, seventy-nine thousand, eight hundred sixty-one".