19897420771 has 2 divisors, whose sum is σ = 19897420772. Its totient is φ = 19897420770.

The previous prime is 19897420757. The next prime is 19897420841. The reversal of 19897420771 is 17702479891.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 19897420771 - 2¹⁵ = 19897388003 is a prime.

It is not a weakly prime, because it can be changed into another prime (19897420871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9948710385 + 9948710386.

It is an arithmetic number, because the mean of its divisors is an integer number (9948710386).

Almost surely, 2^19897420771 is an apocalyptic number.

19897420771 is a deficient number, since it is larger than the sum of its proper divisors (1).

19897420771 is an equidigital number, since it uses as much as digits as its factorization.

19897420771 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1778112, while the sum is 55.

The spelling of 19897420771 in words is "nineteen billion, eight hundred ninety-seven million, four hundred twenty thousand, seven hundred seventy-one".