19917478127 has 2 divisors, whose sum is σ = 19917478128. Its totient is φ = 19917478126.

The previous prime is 19917478117. The next prime is 19917478129. The reversal of 19917478127 is 72187471991.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 19917478127 - 2⁴ = 19917478111 is a prime.

Together with 19917478129, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19917478129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9958739063 + 9958739064.

It is an arithmetic number, because the mean of its divisors is an integer number (9958739064).

Almost surely, 2^19917478127 is an apocalyptic number.

19917478127 is a deficient number, since it is larger than the sum of its proper divisors (1).

19917478127 is an equidigital number, since it uses as much as digits as its factorization.

19917478127 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1778112, while the sum is 56.

The spelling of 19917478127 in words is "nineteen billion, nine hundred seventeen million, four hundred seventy-eight thousand, one hundred twenty-seven".