21171190423723 has 2 divisors, whose sum is σ = 21171190423724. Its totient is φ = 21171190423722.

The previous prime is 21171190423661. The next prime is 21171190423739. The reversal of 21171190423723 is 32732409117112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21171190423723 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21171190423723.

It is not a weakly prime, because it can be changed into another prime (21171190423223) 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, 10585595211861 + 10585595211862.

It is an arithmetic number, because the mean of its divisors is an integer number (10585595211862).

Almost surely, 2^{21171190423723} is an apocalyptic number.

21171190423723 is a deficient number, since it is larger than the sum of its proper divisors (1).

21171190423723 is an equidigital number, since it uses as much as digits as its factorization.

21171190423723 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 127008, while the sum is 43.

The spelling of 21171190423723 in words is "twenty-one trillion, one hundred seventy-one billion, one hundred ninety million, four hundred twenty-three thousand, seven hundred twenty-three".