19771493897 has 2 divisors, whose sum is σ = 19771493898. Its totient is φ = 19771493896.

The previous prime is 19771493851. The next prime is 19771493909. The reversal of 19771493897 is 79839417791.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19683809401 + 87684496 = 140299^2 + 9364^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19771493897 is a prime.

It is a super-3 number, since 3×19771493897³ (a number of 32 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (19771499897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9885746948 + 9885746949.

It is an arithmetic number, because the mean of its divisors is an integer number (9885746949).

Almost surely, 2^19771493897 is an apocalyptic number.

It is an amenable number.

19771493897 is a deficient number, since it is larger than the sum of its proper divisors (1).

19771493897 is an equidigital number, since it uses as much as digits as its factorization.

19771493897 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24004512, while the sum is 65.

The spelling of 19771493897 in words is "nineteen billion, seven hundred seventy-one million, four hundred ninety-three thousand, eight hundred ninety-seven".