21809179123243 has 2 divisors, whose sum is σ = 21809179123244. Its totient is φ = 21809179123242.

The previous prime is 21809179123099. The next prime is 21809179123247. The reversal of 21809179123243 is 34232197190812.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21809179123243 is a prime.

It is not a weakly prime, because it can be changed into another prime (21809179123247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10904589561621 + 10904589561622.

It is an arithmetic number, because the mean of its divisors is an integer number (10904589561622).

Almost surely, 2^{21809179123243} is an apocalyptic number.

21809179123243 is a deficient number, since it is larger than the sum of its proper divisors (1).

21809179123243 is an equidigital number, since it uses as much as digits as its factorization.

21809179123243 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1306368, while the sum is 52.

The spelling of 21809179123243 in words is "twenty-one trillion, eight hundred nine billion, one hundred seventy-nine million, one hundred twenty-three thousand, two hundred forty-three".