19771564487 has 2 divisors, whose sum is σ = 19771564488. Its totient is φ = 19771564486.

The previous prime is 19771564457. The next prime is 19771564489. The reversal of 19771564487 is 78446517791.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 19771564487 - 2⁸ = 19771564231 is a prime.

Together with 19771564489, 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 (19771564489) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9885782243 + 9885782244.

It is an arithmetic number, because the mean of its divisors is an integer number (9885782244).

Almost surely, 2^19771564487 is an apocalyptic number.

19771564487 is a deficient number, since it is larger than the sum of its proper divisors (1).

19771564487 is an equidigital number, since it uses as much as digits as its factorization.

19771564487 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11854080, while the sum is 59.

The spelling of 19771564487 in words is "nineteen billion, seven hundred seventy-one million, five hundred sixty-four thousand, four hundred eighty-seven".