21878497559 has 2 divisors, whose sum is σ = 21878497560. Its totient is φ = 21878497558.

The previous prime is 21878497507. The next prime is 21878497561. The reversal of 21878497559 is 95579487812.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21878497559 is a prime.

Together with 21878497561, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21878497495 and 21878497504.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21878491559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10939248779 + 10939248780.

It is an arithmetic number, because the mean of its divisors is an integer number (10939248780).

Almost surely, 2^21878497559 is an apocalyptic number.

21878497559 is a deficient number, since it is larger than the sum of its proper divisors (1).

21878497559 is an equidigital number, since it uses as much as digits as its factorization.

21878497559 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 50803200, while the sum is 65.

The spelling of 21878497559 in words is "twenty-one billion, eight hundred seventy-eight million, four hundred ninety-seven thousand, five hundred fifty-nine".