21723893881559 has 2 divisors, whose sum is σ = 21723893881560. Its totient is φ = 21723893881558.

The previous prime is 21723893881523. The next prime is 21723893881589. The reversal of 21723893881559 is 95518839832712.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21723893881559 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 21723893881492 and 21723893881501.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21723893881589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10861946940779 + 10861946940780.

It is an arithmetic number, because the mean of its divisors is an integer number (10861946940780).

Almost surely, 2^{21723893881559} is an apocalyptic number.

21723893881559 is a deficient number, since it is larger than the sum of its proper divisors (1).

21723893881559 is an equidigital number, since it uses as much as digits as its factorization.

21723893881559 is an evil number, because the sum of its binary digits is even.

The product of its digits is 261273600, while the sum is 71.

The spelling of 21723893881559 in words is "twenty-one trillion, seven hundred twenty-three billion, eight hundred ninety-three million, eight hundred eighty-one thousand, five hundred fifty-nine".